
Class 

Book. 

Copyright N°_ 



COPYRIGHT DEPOSIT. 



HYGIENE 

DENTAL AND GENERAL 



BY 

CLAIR ELSMERE TURNER 

ij 

ASSISTANT PROFESSOR OF BIOLOGY AND PUBLIC HEALTH IN THE MASSA- 
CHUSETTS INSTITUTE OF TECHNOLOGY; ASSISTANT PROFESSOR 
OF HYGIENE IN THE TUFTS COLLEGE MEDICAL 
AND DENTAL SCHOOLS 



AVith Chapters on 

DENTAL HYGIENE AND ORAL PROPHYLAXIS 

By William Rice 
i 

Dean, Tufts College Dental School 



ST. LOUIS 
C. V. MOSBY COMPANY 

1920 



kl J 



-&? 



Copyright, 1920, By C. V. Mosby Company 

(All Rights Reserved) 



Press of 

C. V. Mosby Company 

St. Louis 



AUG 3U I^u @cu5762 i7 



TO 
MY MOTHER 

This book is 
Affectionately Dedicated 



PREFACE 

There are many reasons why the dentist should have an 
authentic and fundamental knowledge of hygiene. Whether 
willingly or unwillingly, he is placed in the position of an 
adviser. The ordinary practice of his profession is not alone 
concerned with the hygiene of the mouth. Troubles which he 
is endeavoring to prevent, correct and improve, affect the gen- 
eral health and are reacted upon by it. Moreover many peo- 
ple consult the dentist who do not visit a physician and to 
most of these he is a "doctor" who is expected to know not 
only the facts relating to infection, but also the rules for 
health. Many a practicing dentist can testify that he is 
questioned on every health problem from diet to municipal 
sanitation. 

How much ought the dentist to know about these subjects? 
Obviously he should have the most definite knowledge avail- 
able upon the interrelationship between abnormal conditions 
of the mouth and other organic and systemic defects. His 
knowledge of the danger of transmitting disease in dental 
practice should be equally definite. The rules of personal 
hygiene are of use to him not only in regulating his own 
living but also in getting the best results with his cases. To 
prescribe a schedule of hygienic living will often do as much 
as an office treatment in getting the patient into a normal con- 
dition. 

Public health activities also have a right to claim the at- 
tention of the dentist. He is coming to take an increasingly 
larger part in municipal, school and industrial Hygiene and 
lie should know the powers, organization and responsibility 
of the health agencies of the government. But apart from 
these fields in which he is interested professionally he has 
special duties of citizenship, for his training has given him a 
basis for appreciating the value of hygiene and sanitation. 
Excepting possibly the physician and sanitarian no one in 
the community can so well understand the possibilities and 

5 



b PREFACE 

advantages of efficient public health administration. The 
dentist may well be expected to assume some degree of lead- 
ership in these matters and if he is able to do so successfully 
his standing in the community is markedly benefited both 
socially and professionally. 

There has hitherto been no treatment of the subject of hy- 
giene specially prepared to meet the needs of the dental pro- 
fession. In writing this book for the dental student and prac- 
titioner, special attention has been given to those phases of 
the subject which relate to dental practice wherever they 
occur. 

In arranging the order of the text, those aspects of both 
dental and personal hygiene that are not related to infection 
are first considered. Then follows a discussion of the de- 
velopment of the new science of disease prevention and its 
effect upon dental practice, personal hygiene, and the public 
health. 

The author desires to acknowledge gratefully the assistance 
received from many persons in the criticism of the manu- 
script. In particular thanks are due to Professor Percy Gr. 
Stiles of the Harvard Medical School for reading some of the 
manuscript on personal hygiene and for assisting in the prep- 
aration of a diagram of the autonomic nervous system. 
Special thanks are also due to Dr. F. H. Slack for reading 
the chapter on immunity, to Dr. F. A. Woods for suggestions 
in connection with the material on heredity, to Dr. A. 
LeEoy Johnson for assistance in the chapter on oral hygiene, 
and to other teaching associates for stimulating and helpful 
suggestions. 

The author also wishes to express appreciation to Professor 
C.-E. A. Winslow for permission to use cuts number 6, 9, 10, 
29 and 31 from Healthy Living, to Dr. Lawrence Baker for 
permission to use cuts number 3 and 4 from one of his unpub- 
lished researches, and to the many others who have assisted in 
securing illustrative material. ^ -p t> ttrnfr 

Massachusetts Institute of Technology, 
Cambridge, Mass. 



CONTENTS 

CHAPTER I 
DENTAL HYGIENE 

PAGE 

The Divisions of Personal Hygiene — Hygiene of the Mouth — The 
Form and Arrangement of the Teeth — Contact and Occlusion 
— Orthodontia — Function — Deforming Habits — Structure of 
the Teeth— The Investing Tissues— The Saliva 17 

CHAPTEE II 

THE HYGIENE OF NUTRITION 

Diet — Water — > Nitrogenous Foods — Carbohydrates — Fats — Inor- 
ganic £>alts — Vitamines — Dietary Diseases — Balanced Diet — 
The Varied Diet — Digestion — Digestion and the Emotions — 
The Hygiene of the Emotions — Mastication — Water with 
Meals — Rest after Eating — Assimilation — Assimilation Defined 
— Oxidation — Eliminating the Body Wastes — Autointoxica- 
tion — Constipation — Food Poisoning — Obesity — Under-eating 
— Conclusions 33 

CHAPTER III 

THE HYGIENE OF ACTION 

Two Kinds of Bodily Activity — Exercise — What Exercise Does 
for the Body — Types of Physical Exercise — Rhythm in Exer- 
cise — Walking — Ordinary Body Activities — Figure — Round 
Shoulders — Carrying the Head Forward — Spinal Curvatures — 
Deformities of the Feet — Ocular Hygiene — Breathing — Bath- 
ing — Clothing 54 

CHAPTER IV 

THE HYGIENE OF THE CENTRAL NERVOUS SYSTEM 

Function — Concentration — Habit — Sleep — Dreams — Change of 
Work — Sunday Observance — Neurasthenia — Overwork — Emo^ 
tions — Bodily Defects — Stimulants — The Neurasthenic ... 68 

CHAPTER V 

THE HYGIENE OF REPRODUCTION 

The Problem Defined — Heredity— Mendelian Inheritance — How 
Sex in Offspring is Determined — Sex Linked Characters — In- 
herited Diseases and Abnormalities — Mentality and Heredity 
— Feeble-mindedness— Heredity and Conduct — Prenatal Care — 

7 



8 CONTENTS 

PAGE 
Standards for Maternity Care — Infant Care — The Obligation 
of the Community to the Infant and the Preschool Child — Sex. 
Hygiene — Sex Education — Summary — The Child's Ten Com- 
mandments to Parents 80 

CHAPTER VI 

THE NEW SCIENCE OF DISEASE PREVENTION 

Communicable Diseases — Early Theories of Disease — Fore-shadow- 
ings of the Present Theory — Fermentation and Disease — 
Pasteur — Lister — Koch and the Development of Bacteriology 
— Preventive Medicine — Smallpox and Vaccination — Immunity 
in Anthrax and Rabies — Diphtheria and Antitoxin — Preven- 
tive Sanitation — The Epidemic of the Broad Street Well — A 
Typhoid Fever Epidemic from Oysters— Preventive Hygiene 
— Resistance — Summary 108 

CHAPTER VII 

THE ESSENTIAL FACTS OF IMMUNITY 

Immunity Defined — Nonspecific Immunity — Fatigue — Exposure to 
Wet and Cold — Drugs — Under-eating — Oral Defects — Specific 
Immunity — Natural Immunity — Local Immunity — Acquired 
Immunity — Active and Passive Immunity — Carriers — Disease 
Reactions — Toxins — Endotoxins— Tractive Phenomena — Phag- 
ocytosis — Anaphylaxis — Specific Substances — Theories of Im- 
munity — Exhaustion Theory — Retention Theory — Phagocytic 
Theory— Side Chain Theory -. .... 125 

CHAPTER VIII 

ORAL PROPHYLAXIS 

Caries — Diet in Relation to Decay — The Care of the Gums and 
Gingivae — Gingivitis — Deposits — Prophylactic Treatment — 
The Dental Hygienist— Daily Care of the Teeth— Method of 
Brushing the Teeth — Care of the Brush — Dental Floss — Tooth- 
picks — Mouth Washes — Tooth Powders and Pastes — Tooth 
Cleansing Foods — Care of the Mouths of Children — Septic 
Teeth as a Source of Systemic Disease 144 

CHAPTER IX 

COMMUNICABLE DISEASES 

Three Great Plagues — Tuberculosis — Prevalence — The Difficulties — • 
Transmission of Tuberculosis — Prevention and Control — Syph- 
ilis — Importance — Nature of the Disease — Transmission — Im- 
munity — Prevention — Educational Program — Common Cold — 
The Cause of Colds — Catching Cold — Influenza — Cause — Mor- 
bidity and Mortality Rates — Immunity — Control 165 



CONTENTS 9 

PAGE 
CHAPTER X 

PUBLIC HEALTH ADMINISTRATION 

Public Health Authority— Federal Public Health Fuuctions— The 
Power to Regulate Commerce — Taxation — Defense and Wel- 
fare Powers — Treaty and War Powers — The U. S. Public 
Health Service — Other Federal Agencies — State Health Func- 
tions — Public Health Laws — State Health Administration — Or- 
ganization — Administrative Functions — Local Health Adminis- 
tration — Authority — Local Health Organization — The Health 
Officer— Unofficial Health Activities 188 

CHAPTER XI 

FOOD CONTROL 

Food Adulteration — Cost of Adulteration — Nature and Cause of 
Adulteration — Pure Food Laws — Misbranding — Law Enforce- 
ment — Food Sanitation — Milk — Graded Milk — Remade Milk — • 
Meat — Dangers in Meat — Prepared Food 209 

CHAPTER XII 

WATER SUPPLY 

What Is Good Water — Sources of Water Supply — Water Analysis 
— Environment — ' Bacteriological Study — Physical Tests — 
Chemical Tests — Nitrogen and the Nitrogen Cycle — Chlorine — 
Microscopic Analysis — Water Purification — Storage — Filtration 
— Chlorination 22(3 



CHAPTER XIII 

WASTE DISPOSAL 

Sewage Disposal — Direct Disposal — Chemical Purification — Bac- 
teriological Purification — Aerobic Processes — Anaerobic Proc- 
esses — Possibilities and Limitations of Sewage Purification — 
Rural Sanitation — Report of the A. P. H. A. Committee . . 243 

CHAPTER XIV 

SCHOOL HYGIENE 

The Problem — Special Groups of Defectives— The Scope of School 
I [ygieni — Health Control — Personnel — Physical Examination 
— Treatment — Administration — Defect ive Vision — The Dental 
Care of School Children — Teaching Hygiene in Schools — 
School Hygiene and Sanitation — Age and Sex Differences — 
Standards ' 274 



10 CONTENTS 

PAGE 

CHAPTER XV 

INDUSTRIAL HYGIENE 

General Aspects of Industrial Hygiene — General Problems — Hours 
of Work — Fatigue — Child Labor — Women in Industry — Fac- 
tory Inspection — Health Administration in Industry — Accident 
Prevention — Industrial Sanitation — Food — Medical Activities 
— Industrial Dentistry — Disease Prevention and Health Edu- 
cation — Industrial Diseases — Lead Poisoning — Phosphorus 
Poisoning — Mercury Poisoning — Benzene Compounds — Acids 
— Protection against Industrial Poison 301 

CHAPTER XVI 

VENTILATION, HEATING AND LIGHTING 

Good Air Defined — Temperature — Moisture — Odors — Testing Air — 
The Sling Psychrometer — The Hygrodeik — The Polymeter — 
The Comfort Meter — Ventilation and Heating — Natural Ven- 
tilation — Artificial or Mechanical Ventilation — Moisture in the 
Air — Air Washing and Humidifying Cooling Air — The Eco- 
nomic Value of Good Ventilation — Lighting — Office Lighting . 323 

APPENDIX A 

THE CONTROL OF COMMUNICABLE DISEASES 

The American Public Health Association Committee Report upon: 
Actinomycosis — Acute Infectious Conjunctivitis — Ankylosto- 
miasis (Hookworm) — Anthrax — Cerebrospinal Meningitis — 
Chicken P'ox — Cholera — Dengue — i Diphtheria — Dysentery 
(Amebic) — Dysentery (Bacillary) — Favus — German Measles — 
Glanders — Gonorrhea 1 — Leprosy — Malaria — Measles — Mumps 
— Paratyphoid Fever — Plague — P'neumonia (Acute Lobar) — 
Poliomyelitis — Rabies — Rocky Mountain Spotted or Tick Fe- 
ver — Scarlet Fever — Septic Sore Throat — Smallpox — Syphilis — 
Tetanus — Trachoma — Trichinosis — Tuberculosis (Pulmonary) 
— Tuberculosis (Other than Pulmonary) — Typhoid Fever — 
Typhus Fever — Whooping Cough — Yellow Fever 339 

APPENDIX B 

DISINFECTION AND DISINFECTANTS 

Definitions — Disinfection versus Sterilization — Antiseptics — Deodo- 
rants — Fumigation — Disinfection — Control of Disinfection — 
Natural Disinfection — The Ideal Disinfectant — Standardizing 
Disinfectants — Physical Agents of Disinfection — Gaseous Dis- 
infection — Formaldehyde Gas — Sulphur Dioxide — Oxygen — Hy- 
drocyanic Acid — Liquid Disinfectants — Mercuric Chloride — 
Formalin — Potassium Permanganate — Lime — Whitewash — Milk 
of Lime — Disinfection in Dental Practice — Hands — Materials 
—The Office 378 

Bibliography 389 

Index 394 



ILLUSTRATIONS 

FIG. PAGE 

1. Model illustrating normal occlusion 20 

2. Model illustrating normal occlusion 21 

3. Asymmetric development of the bones of the skull of a dog . 22 

4. Upper aspect of the skull shown in Fig. 3 23 

5. Deformity from lack of function 24 

6. Air passages of the mouth and nose showing their relationship 

to the adenoids and tonsils 25 

7. Deformity due to thumb sucking . . . 26 

8. Diagram illustrating groups of fibers of the gingivae and peri- 

dental membrane *..<,,.., 29 

9. The composition of cow's milk 40 

10. Portions of different foods each yielding approximately 100 

calories of heat energy 41 

11. Diagram, showing the most important distributions of the auto- 

nomic nervous system 46 

12. The worry-auto-intoxication cycle 50 

13. Good and bad postures 60 

14. Posture chart showing the result of the examination of Har- 

vard Freshmen . 61 

15. Inheritance in guinea pig showing where one color dominates 

over another color 81 

16. Diagram illustrating the mechanism by which the unit factor, 

color, is inherited in guinea pigs .83 

17. Eminent twins 84 

18. Transmission of color blindness 87 

19. Cholera deaths in the epidemic of the Broad Street Well . . 119 

20. Diagram illustrating the three orders of immunity as described 

in Ehrlich's Side Chain Theory of Immunity 141 

21. Deformity resulting from neglect of the teeth 144 

22. Showing malocclusion due to caries 145 

23. Diagram illustrating nomenclature of gingiva) 149 

24. Diagram illustrating nomenclature of gingivae 149 

25. Dental hygienists in Prophylactic Clinic at Forsyth Dental In- 

firmary for Children 154 

26. Tooth brushes of proper shape and material 158 

11 



12 ILLUSTRATIONS 

FIG. PAGE 

27. Comparative figures showing the number of disease and battle 

deaths each year per thousand troops in the wars of the 
United States 166 

28. The relative proportion of army deaths caused by the principal 

diseases in the war with Germany 167 

29. An inexpensive and easily constructed outdoor sleeping porch . 173 

30. Chart showing the time and temperatures at which bacteria 

are killed and at which the quality of the milk is changed . 217 

31. Pasteurization of milk at home 218 

32. Pollution of wells by water which soaks through the soil from 

privies or cesspools 229 

33. The nitrogen cycle 232 

34. Diagram shoAving the condition of the stream studied at Brock- 

ton 237 

35. Diagram showing the abundance of microorganisms at the va- 

rious sampling stations 238 

36. Shows how completely the higher aquatic plants fill part of 

stream in summer 239 

37. Showing how differently the same region appears under winter 

conditions and high-stream flow 239 

38. A chemical closet installed in a home where running water is 

not available 245 

39. Eemoving the sludge from the sand beds at the Brockton Sew- 

age Purification Works 248 

40. Imhoff tank 252 

41. Sewage purification plant in Atlanta, Ga. 254 

42. A single-seated sanitary privy 260 

43. Bear and side view of privy 261 

44. Outdoor incinerator (Arnold type) 268 

45. Floor plan and arrangement of medical inspector's room gen- 

erally followed in New York City 281 

46. The effect of treatment for adenoids upon the general appear- 

ance of three children 284 

47. Errors in refraction . . . , 285 

48. Dental Clinic at the Forsyth Dental Infirmary for Children . 290 

49. Wet and dry bulb thermometer 327 

50. Sling psychrometer 328 

51. Hygrodeik instrument 329 

52. Portable foot candlemeter 338 



FOREWORD 

By William T. Sedgwick, Sc.D. 

Professor of Biology and Public Health, Massachusetts Institute of 

Technology, Chairman Harvard-Technology School of 

Public Health, etc. 

Whoever regards the human mechanism objectively cannot 
fail to be struck with the growth and function of its harder 
parts. Bones, nails and teeth, though wanting in the early 
embryo, are rapidly formed soon after independent life begins. 
The bones, securely covered, are rarely exposed to decay or 
wear, and the skeleton in age is in many respects more com- 
plete and perfect than in youth. But with the teeth it is 
otherwise. Pushing outwards through the soft parts these 
are very early exposed to unfavorable conditions and, like 
knives and millstones, become dull and worn with use. Even- 
tual) y, if not forcibly removed they fall out, so that at the end 
of life man is often "sans teeth," though not "sans every- 
thing" — no other organs of the body except the hair and epi- 
dermis being thus deciduous. 

Hence it is that the teeth for their protection require un- 
usual care — a fact now generally recognized by the rise of the 
dental profession and the popular enthronement of the tooth- 
brush. But scientific care of any of the organs of the body is 
neither more nor less than hygiene, so that Dental Hygiene — 
the scientific care of the teeth — is one of the fundamentals 
of all hygiene. And since the human body is not merely an 
assembly of discontinuous and unrelated parts, but rather a 
complete entity or organism — originally homogeneous and 
never more than incompletely differentiated — so much so that 
the hand cannot say to the foot, or the brain to the teeth, 
"I have no need of thee" — it follows that dental hygiene is 

13 



14 FOREWORD 

only a part of General Hygiene. Accordingly, while this book 
deals with the hygiene of the teeth and takes its beginnings 
with the teeth it does not — because it cannot — end there. 
Foods and feeding, the flow of saliva, the blood stream and the 
lymph drains and, more remotely but not less surely, sleep 
and rest, work. and play, muscular activity and mental fatigue 
— all these and many more aspects of general hygiene con- 
tribute to the welfare of the teeth. Conversely, the health or 
disease of the teeth plays an all-important part in the wel- 
fare of the other organs of the body and of the body as a 
whole, as all know who have been incapacitated by acute 
toothache. 

Professor Turner's is the first work which, taking for its 
principal field the hygiene of a single set of organs, reaches 
out from these to the rest of the body. And perhaps it is 
for this reason that our textbooks of hygiene have so often 
hitherto been comparatively uninteresting and ineffective. 
It may be that they have been too general and in seeking to 
tell all things about hygiene have failed to tell any well. It 
is for this reason among many that I predict for this work 
an unusually hearty welcome, for those who read it attentively 
will find that while the text of the sermon is dental hygiene, 
and while the teeth — as in the speaking human face — are al- 
ways near and much in evidence, the lessons taught apply 
quite as well to the entire human body and its effective con- 
servation. Such conservation, however, not only requires 
careful consideration of the human body but of that environ- 
ment with which the body deals and which plays upon it from 
birth to death. 

Fifty years ago the slogan for health was mens sana in 
corpore sano — an admirable aphorism but one curiously typ- 
ical of a neglect of environment characteristic of the pre- 
Darwinian period. Nowadays we know only too well that 
the sound mind and the sound body are unavailing for the 
conduct of normal living unless the environment with which 



FOREWORD 15 

they have to deal consists of fairly good air, fairly pure water, 
fairly good food, and is fairly free from communicable dis- 
eases, unfavorable temperatures, defective ventilation, dirt, 
noise and other prejudicial sanitary conditions. Hence, Pro- 
fessor Turner surveying the whole field of dental and general 
hygiene has found it necessary to reach out beyond the teeth 
and other organs of the body, and even beyond the body itself, 
to a consideration of those environmental factors which con- 
tribute so heavily to health or disease, with the result that his 
work is not merely novel and comprehensive, but also original, 
logical and representative of the best hygienic thought of the 
time. 



HYGIENE: DENTAL AND GENERAL 



CHAPTER I 
DENTAL HYGIENE 

Hygiene or the science of healthful living furnishes to man 
the basis for a rational control over those habits and con- 
ditions of existence which affect for good or ill the smooth 
and normal operation of the body mechanism. The develop- 
ment of healthful habits of life depends primarily upon the 
individual, but the maintenance of healthful living conditions 
is largely beyond individual control, and the responsibility 
rests upon organized society. In the restricted sense hygiene 
considers the health of the individual, sanitation the control 
of the environment. 

In considering the hygiene of both the mouth and the body 
as a whole there are two distinct sets of problems: (1) the 
proper development and normal functioning of the parts and 
(2) the problems arising because of infectious organisms. In 
this book the two subjects are separated, the first-mentioned 
receiving consideration in the first five chapters. 

The Divisions of Personal Hygiene. — Personal Hygiene as 
contrasted with public hygiene or public health considers 
those principles and activities for the promotion of health 
over which the individual has control, and to determine the 
scope of this science we have to consider the functions of man 
as an animal. In blunt and simple language nature has de- 
creed that man shall eat, work, think, and breed. The zo- 
ologist expresses this idea more elegantly and scientifically 
by saying that the particular functions of animals are assim- 
ilation, action, sensation, and reproduction. Accepting either 
set of terms in their broad sense we may group the problems 
of Personal Hygiene under these four heads: 

17 



18 HYGIENE: DENTAL AND GENERAL 

1. Hygiene of Nutrition. 

2. Hygiene of Action. 

3. Hygiene of the Central Nervous System. 

4. Hygiene of Reproduction. 

HYGIENE OF THE MOUTH 

The subject of Hygiene concerns the health of the body 
in all its parts and there is no natural division which 
makes it necessary to consider any particular portion of the 
body under a separate head; nevertheless Dentistry is such 
a distinct and highly specialized subject that it will certainly 
be profitable to treat the hygiene of the mouth in detail and 
apart from the above mentioned divisions, for the dentist's 
interest is of necessity centered upon oral conditions and, for 
this reason, he should be able to speak with authority upon 
the means available for the preservation of the health of the 
various oral structures and of the relationship of oral health 
to the general well-being of the entire organism. We are 
perhaps warranted therefore in adding another division of 
the subject for the purposes of this volume, namely the Hy- 
giene of the Mouth. 

In the treatment of this subject it seems desirable to con- 
sider it under two heads: (1) Proper development and nor- 
mal functions of the oral structures (Chapter I), and (2) The 
treatment and prevention of unhygienic or septic conditions 
(Chapter VIII). 

We will consider the means provided by nature for the 
maintenance of oral health under four headings, as follows: 

1. Form and arrangement of the teeth. 

2. Structure. 

3. Investing tissues. 

4. Saliva. 

1. The Form and Arrangement of the Teeth should be 
such that their relationship offers the highest degree of corre- 
lation ; each tooth performs its functions as a dependent unit 



DENTAL HYGIENE 19 

in a perfect machine operated under the motive power of the 
muscles of mastication. 

A study of normal conditions is necessary and a concep- 
tion of the normal should be constantly held in mind as a 
definite picture. The question may well be asked: What is 
the normal? Does it ever exist in fact? Johnson defines 
normal as applied to morphology as signifying "a standard 
determined by constancy. ' ' 

The teeth are in four classes, incisors, cuspids, bicuspids 
and molars, each class designed for a particular function 
in the process of mastication. The type or form of the teeth 
in each of these classes varies according to the shape of the 
face of the individual, as Williams has shown in his classic 
work. ("Classification of Human Tooth Forms," Journal 
of the Allied Dental Societies, Vol. IX, No. 1.) 

Contact and Occlusion. — When the teeth are in normal 
alignment the approximating surfaces of the teeth in each jaw 
are in actual contact at one point, known as the contact point. 
The object of this contact is the protection of the investing 
tissues. This is accomplished by preventing the crowding of 
food into the interproximal spaces. Any deviation from nor- 
mal alignment or the loss of any tooth in the arch, (with the 
possible exception of the third molar) will result in impair- 
ment of function and a loss of the protection to the in- 
vesting tissues; and opportunity w T ill be afforded for the 
crowding of food material between the teeth, thereby establish- 
ing a condition favorable to fermentation and putrefactive 
changes. 

The alveolar process, which is the bony tissue surrounding 
the roots of the teeth, is a temporary structure designed to 
furnish support to the teeth while present within the jaw. It 
is built up around the roots of the teeth as they develop after 
the eruption of their crowns and is removed by the process 
of absorption after the loss of any tooth. It follows, there- 
fore, that after the premature loss of a tooth and the removal 
of its supporting process, no stimulus remains for bone devel- 



20 HYGIENE: DENTAL AND GENERAL 

opment; the continuity of the entire arch is broken and the 
teeth tend to drift in the direction of least resistance. This 
results inevitably in the loss of the normal relationship be- 
tween the approximating surfaces of the teeth of each jaw 
as well as the occlusal relationships of the teeth in opposing 
jaws. Serious deformity may follow. 

Smith has shown {Journal of the Allied Dental Societies, 
Vol. I, April, 1906) that in certain cases of malocclusion the 
timely and well judged extraction of teeth may result bene- 
ficially by relieving the crowded condition. The tendency of 
the drift may then bring the surfaces of the remaining teeth 
into positions closely simulating the normal. 




Fig. 1. — 'Model illustrating normal occlusion. 

Orthodontia. — We agree with Johnson that the attainment 
of the ideal normal occlusion of the teeth by orthodontic 
interference is not always possible and in many cases an 
attempt to bring this about will result in an inharmony in 
the relationship of the teeth to the general contour of the 
bony and muscular structures of the face which nature will 
not tolerate. Not only will it be impossible to retain the teeth 
in their new position, which is an abnormal one, but there 
may ultimately result a deformity more objectionable than 
the original condition. Extensive orthodontic treatment 



DENTAL HYGIEXE 21 

should be undertaken only after a careful study of all pre- 
vailing conditions by one whose vision is not limited to the 
teeth alone. It is futile to attempt to permanently establish 
ideal normal occlusion when all the forces of nature are being 
exerted to maintain the position of the teeth in their relation- 
ship to the organism as a whole. 

Development. — Let us revert to the period of development. 
Baker has shown in his researches upon animals that the 
normal development of the dental arches is dependent upon 
the presence within the jaw of the developing teeth. The 
development of the bone is synchronal with the development 
of the roots of the teeth. The removal of the teeth from one 
side of the jaw was shown to cause an arrested development 
of the bone which resulted in marked deformity. The in- 
harmony of the side of the face from which the teeth were 
removed was very apparent. It was further demonstrated 




Fig. 2. — Model illustrating normal occlusion. 

that normal development of the entire bony structure of the 
head is to a certain extent dependent upon the proper develop- 
ment of the teeth. 

Function. — Among the causes of malocclusion must be con- 
sidered the dependence of development upon function. For 
instance, a study of the organs of mastication of the anthro- 
poid ape (man's prototype) reveals massive structure, de- 
manded by the functional activity incident to the mastication 
of the kind of food available for his sustenance and upon 
which his existence depended. 



22 



HYGIENE: DENTAL AND GENERAL 



With the development of modern methods for refining the 
raw materials to be used as food and the acquirement of the 
epicurean habit — which demands the preparation of complex, 
highly seasoned food calculated to stimulate pleasurable sen- 




Fig. 3. — Observe the asymmetric development of the bones of the skull of a 
dog due to the interference with the function of the upper left lateral half 
of the dental apparatus. 



sations in those whose appetites are already satiated by over- 
indulgence — the necessity for vigorous muscular effort has 
been removed and the stimulating effect of vigorous function- 
ing has been lost. The lower part of the face has thus been 



DENTAL HYGIENE 



23 



reduced in size but the teeth have not relatively changed. The 
result is that the teeth of many people are out of harmony in 
size with the rest of the features. 

All variations from the normal in the development of the 




Fig. 4. — Upper aspect of the skull shown in Fig. 3. 

various units, which are interdependent, must of necessity 
affect the proper functioning of the organism as a whole and, 
therefore, become problems in hygiene. 

Although there is a difference of opinion on this subject, 



24 



HYGIENE: DENTAL AND GENERAL 



there are orthodontists who believe that the normal develop- 
ment of the oral structures is also impeded by substituting 
the artificial feeding of the infant in the place of breast 
feeding. "Whoever has observed carefully the infant in the 
act of nursing must have noticed that much exertion is put 
forth in the effort to obtain the milk. It is upon this mus- 
cular effort, and the enforced position of the oral structures 
during the act of sucking and swallowing that normal devel- 
opment is in a considerable degree dependent. No bottle 
feeding device perfectly simulates the breast or affords the 




Fig. 5. — Deformity from lack of function. Ankylosis prevented the movement 

of the jaw. 

vital muscular resistance which supplies the essential stimu- 
lus for the development of the oral structures of the growing 
infant. 

Deforming Habits.— Deformities of the face and jaws aris- 
ing from mouth breathing or other habits contracted in in- 
fancy, such as thumb-sucking and the continued use of pac- 
ifying devices, deserve consideration. 

One of the most common causes of mouth breathing is the 
presence of adenoids in the posterior nares which so fill up 
the space required for normal breathing that the child resorts 



DEXTAL HYGIENE 



25 



to mouth breathing in order to obtain sufficient air. Adenoids 
are enlarged lymphoid follicles. These follicles are normally 
present in the nasopharynx but from various sources of irri- 
tation they frequently become congested and swollen. 

The deformities resulting from the use of pacifying devices 
are frequently seen; and their use either reflects upon the 
intelligence of the parents or they are used in utter disregard 



%X~Adenoids 




Fig. 6. — The air passages of the mouth and nose showing their relationship to 
the adenoids and tonsils. 



of the welfare of the child. In any case the resulting deform- 
ity is a constant rebuke to the neglect of the child. 

The thumb-sucking habit may be overcome by binding the 
arms of the child to its side or by the use of celluloid hand 
protectors. The deformity 'of drawn-in arches which results 
from thumb-sucking is so characteristic as to be unmistakable, 
and not only interferes with the functioning of the teeth but 
destroys the entire contour of the mouth. 

2. Structure of the Teeth. — Nature has protected the 
teeth by furnishing for their outer covering the hardest sub- 



26 HYGIENE: DENTAL. AND GENERAL 

stance to be found in the body. A difference in opinion exists 
in regard to the question of variation in the hardness of the 
teeth in different individuals and at different age periods of 
the same individual. To state the question more explicitly : 
are some teeth hard and others soft? Is this hardness or 
softness of the teeth subject to changes at different periods in 
life, and does nutritional action affect the integrity of the 
enamel rendering it more susceptible to the inroads of caries ? 
Or is this lesion dependent alone upon the oral secretions 




Fig. 7. — Deformity due to thumb sucking. 

which are really determined by systemic conditions? A 
statement of the conclusions of recognized investigators may 
aid in forming an opinion. 

Williams has stated that "enamel is a solid mineral sub- 
stance and the finest lenses reveal not the slightest difference 
between enamel ground moist from a living tooth and that 
which has lain in the earth for hundreds of centuries. " This 
statement would not seem to be borne out by analyses of 
enamel, for according to statistics published from time to 
time, the amount of organic matter varies from two to seven 
per cent. 



DENTAL HYGIENE 27 

Picker ell found that enamel is not impermeable and that 
stain penetrates to a varying depth in different teeth; more- 
over, the permeability varies in ratio to the length of time a 
tooth has been erupted. This would seem to prove that 
enamel does change its character after the eruption of the 
teeth. He also found that the density or compaction of 
enamel was in direct ratio to the time elapsed since its for- 
mation. The hardness of enamel was tested by determining 
the comparative resistance to scratching. The result of his 
experiment seems to be conclusive that there does exist a de- 
cided difference in the hardness of teeth. The hard teeth he 
terms sclerotic, and the soft teeth malacotic. He believes that 
the permeability, density and hardness are important factors 
in the predisposition to caries since malacotic teeth would 
more readily permit the penetration of the oral fluids. 

Black made a series of studies published in the Dental Cos- 
mos in 1895 relative to the hardness of teeth as a whole. His 
experiments bear special reference to the percentage of cal- 
cium salts in dentin, and as the initial lesion in caries always 
takes place in the enamel his conclusions would not seem to 
have a direct bearing on the susceptibility of teeth to caries. 
It may well be that the dentin of teeth is practically uniform 
in the calcium content. 

Black asserts that the seeming differences in the hardness 
of teeth as reflected by their varied resistance to cutting in- 
struments is due to (1) the direction of approach, (2). to the 
difference in the relation of the enamel rods to each other. 
Since enamel is not a homogeneous structure, but composed 
of hexagonal rods, held together by a cementing substance less 
strong than the rods, it is possible to cleave them along the line 
of their length more easily than in other directions. When 
the rods lie parallel with each other the enamel splits easily; 
on the other hand, in many teeth the enamel rods do not run 
parallel but are curled, twisted and interwoven. This enamel 
would cut with much greater difficulty even if there were no 
difference in amount of calcium salts contained. 



28 HYGIENE: DENTAL AND GENERAL 

Howe in his experiments upon animals has actually pro- 
duced caries by depriving them of their natural food, such as 
green vegetables, milk and other substances rich in mineral 
content. Whether caries was caused by degeneration of the 
tooth structure due to lowered nutrition or whether the nutri- 
tional disturbance influenced the environment (oral secre- 
tions) is a question. 

From a clinical standpoint I feel sure that a consensus of 
opinion would be that the character of the hard tissues of the 
teeth does vary at different periods in life, and the physical 
characteristics of the teeth are affected by the general physi- 
cal condition of the individual. Whether this change comes 
from nutritive disturbances which in some unknown way 
affect the integrity of the tooth structure through the blood 
stream, or whether the changes are solely the result of in- 
fluences from without is yet to be decided. 

3. The Investing Tissues. — The teeth are set in the alveolar 
process which, as has been stated, is developed simultaneously 
with the roots of the teeth, gradually disappearing when its 
function as a supporting structure ceases to exist. It is the 
framework upon which the soft investing tissues are laid and 
in it are the sockets in which the roots of the teeth are set 
and held by their membrane. It envelops the roots of the 
teeth and develops in such a way as to rise to a considerable 
height between the teeth, forming a crest known as the alve- 
olar crest. 

The peridental membrane is the term applied to the soft 
tissues lying between the root of the tooth and the walls of the 
alveolar socket, its function being to attach the teeth to the 
bone of the jaw. Various groups of fibers radiate from the 
peridental membrane to the gingiva? and the alveolar process 
in which they are attached. These fibers not only attach the 
tooth to the alveolar bone but they pass from tooth to tooth 
over the alveolar crest forming a continuous chain connecting 
the teeth from one extremity of the arch to the other. These 



DENTAL HYGIENE 



29 



fibers have the effect of a ligament binding the roots of the 
teeth to the bone. It will be seen that the extraction of any 
tooth literally breaks the continuity of the entire arch. 
The gingiva, resting on the crest of the alveolar process 




Fig. 8. — Diagram illustrating groups of fibers of the gingivae and peridental 
membrane. Bucco-lingual section through a bicuspid tooth and investing tissue. 
F, Free gingiva; group of fillers; Ac, Alveolar crest group of fibers; H, Horizontal 
group of libers; (), Oblique group of fibers; A, Apical group of fibers; B, Bone 
or alveolar process. (Black's "Special Dental Pathology.") 



30 HYGIENE : DENTAL AND GENERAL 

encircles each tooth and rises on the septal crest to a point 
below and near the contact of the proximal surface of the ad- 
joining teeth. This tissue hugs closely the neck of the tooth 
but is not attached to it, the space between the tooth and the 
tissue being known as the sub-gingival space. Any injury to 
this free gingival tissue affects seriously its protective func- 
tion and exposes a vulnerable portion of the tooth to the acid- 
forming bacteria, while the crowding down of the septal gin- 
giva affords a favorable place for the impaction of food 
material. This condition frequently leads to the formation 
of a pocket which, becoming infected, gradually destroys the 
supporting structure of the teeth, causing their loosening and 
eventual loss. 

4. The Saliva. — The role played by the saliva is also a 
very important one among the defensive or protective agen- 
cies, and its presence and constant renewal tends to maintain 
the normal environment of the teeth and to overcome by its 
neutralizing effect the harmful action of fermentation. In 
general terms it may be stated that the saliva is composed of 
water, albumen, mucus, ptyalin and the salts of potassium and 
sodium held in solution. The proportions vary in different 
individuals and in the same individual at different periods of 
the day. The amount of its different components will be af- 
fected by the physical condition of the individual and by the 
kind of stimulation inciting its now. 

Cannon has shown in his experiments on animals that the 
digestive fluids are greatly influenced both in amount and 
composition by the mental state of the animal. The mental 
impression produced by the sight or odor of food also has a 
similar effect. The old saying that a certain food makes the 
mouth water has its basis in fact. The mere thought of 
savory food or acid fruits is sufficient to stimulate the glands 
to increased functioning. 

Saliva varies also in its physical characteristics from a 
thick, viscid, mucilaginous substance rich in albumen and 
mucus to a thin watery fluid containing small quantities of 



DENTAL HYGIENE 31 

colloid material. Carbon dioxide is always present in the 
saliva as in the blood and other body fluids. 

The action of the ptyalin content is to convert starch into 
sugar during the process of mastication. Thorough masti- 
cation is essential to obtain the full effect. The sense of 
taste will quickly detect the change taking place, the sweet 
taste increasing as the chemical action proceeds. According 
to Black the ptyalin has a still further function in freeing 
the surfaces of the teeth and the embrasures of the clinging 
particles of starchy foods which remain after the mass has 
been swallowed. Pickerell also suggests that the principal 
function of the saliva is the hydrolysis of the starches. 

The function of mucus in the saliva is largely a mechanical 
one. It lubricates and makes slippery all the surfaces of the 
tissues. It coats the teeth and imparts to their surfaces a 
smoothness and softness not otherwise obtainable. During 
mastication it mixes with the food and prevents it from stick- 
ing to the surfaces of the teeth, gums and mucous membrane 
of the mouth. It aids in forming the bolus of food which 
makes easy the act of swallowing. A deficiency in the amount 
of mucus will be evidenced by difficulty in the management 
of food in the process of mastication. 

The wafer of the saliva acts by its presence, bathing the 
surfaces of the teeth, this action being promoted by the move- 
ment of the muscles of the cheeks and tongue, by which it 
may be forced through the interproximal spaces or drawn 
through by the action of suction. The habitual use of this 
function as a regular exercise in performing the toilet of the 
teeth may be of marked benefit. 

Thorough mastication also influences not only the quantity 
and quality but the composition of the saliva. The alkalinity 
of the saliva is dependent upon its ash content and with an 
increased flow brought about by the stimulating influence of 
the exercise of mastication the ash content is increased and 
consequently the alkalinity proportionately raised. It has 
been shown by Pawlow that glandular secretions have the 



32 HYGIENE: DENTAL AND GENERAL 

property of adaptation ; in other words the degree of alkalin- 
ity is largely influenced by the character of the food to be 
acted npon. In periods of physiologic rest the saliva is 
weakly alkaline and the quantity secreted is only about 1 c.c. 
per minute, this amount being greatly increased during the 
period of active functioning, the increase depending largely 
upon the nature of the food material. It is interesting to note 
that in cases of dry mouth the teeth quickly crumble away. 
A marked increase in caries is usually noted in any pathologi- 
cal disturbance of glandular activity. Prinz states that "the 
quality of the secreted saliva is the sole factor which governs 
environmental phenomena concerning tooth decay." 



CHAPTER II 

THE HYGIENE OF NUTRITION 

The process of keeping the body in a properly nourished 
condition is complex. It demands the consumption of suit- 
able foods in proper quantities, adequate digestion, the trans- 
mission of these digested foods to the parts of the body where 
they are finally used, the burning of the fuel foods, the re- 
building or growth of the tissue, and the elimination of the 
waste products of cell activity. The Hygiene of Nutrition 
may be divided into the problems of (1) diet, (2) digestion, 
and (3) assimilation. 

1. DIET 

Many people worry about how to get the foods they like, 
but few think much about choosing the foods which the body 
demands. Indeed if one led an active and normal life and 
could choose freely among the foods he likes he could, to a 
large extent, rely upon his natural taste to select the proper 
diet. To select a diet scientifically or to know where the un- 
scientific method breaks down, however, we must understand 
the nutritional needs of the body. 

These dietary needs may best be understood by studying 
the products of digestion which finally pass through the walls 
of the stomach and intestines. Were you able to accomplish 
the gastronomic feat of sampling every product exhibited at 
a food fair, there would be from all this food but six types 
of digestive products finally reaching the body tissue. To ex- 
plain : if we regard the body as a tube within a tube, as we 
properly may, then the material in the digestive tract is not 
in the body proper; it is merely in contact with the "inner 
skin" and may only reach the body by penetrating the intes- 
tinal wall. Such penetration is accomplished by only six kinds 

33 



34 HYGIENE: DENTAL AND GENERAL 

of substances : (1) water, (2) amino acids, (3) simple sugars, 
(4) products of fat digestion, (5) inorganic salts, and (6) 
vitamines. What is the use of each of these food materials 
in the body? Why and how must we provide a diet which 
will insure the proper amount of each? 

Water makes up two-thirds of the body weight and in ac- 
tive tissues like muscle it is three-fourths the total weight. 
Moreover, the body has a liquid carrier system. The blood 
and lymph, which are mainly water, carry food to the tissues 
and remove from them the waste products of combustion. The 
chief way of eliminating waste nitrogen from the body is by 
means of the water passing through the kidneys. Every in- 
dividual knows that in making thirst more painful than 
hunger nature has set a very high demand upon the water 
diet. 

So important is the activity of water that we might almost 
speak of a distinct water circulation consisting of the passage 
of water from the diet into the body and its elimination from 
the lungs in the form of moisture, from the skin in the form of 
sweat, and through the kidneys in the form of urine. The 
amount of water excreted in these ways by an active man in 
the course of a day amounts to over two quarts. Yet in spite 
of these facts a deficiency of water in the diet, especially 
among people engaged in a sedentary occupation, is a most 
common and serious fault. 

Water may be obtained in the diet in a variety of ways. 
The greatest quantity of course, is obtained through drinking 
water and other beverages, like tea and coffee, but much also is 
obtained from the solid food. This is notably the case with 
fruits and vegetables many of which contain over 90 per cent 
of water. Watermelon is 98 per cent water. Soup and broth 
are also sources of water supply in the diet. The amount of 
water necessary for proper waste elimination and for feeding 
the tissues in an individual of average weight is four or five 
pints per day. Of this, at least six glasses should be drunk 
in the form of water itself. 



HYGIENE OF NUTRITION 35 

Nitrogenous Foods. — The chemically simple products of 
protein digestion are the amino acids. They are the sub- 
stances from which new tissue is built up in the growing body, 
and from which worn-out tissue is replaced in the adult. 
These compounds are sometimes called the building stones of 
tissue substance because they recombine on the other side of 
the intestinal wall and in the various parts of the body to 
form the typical body proteins. These substances, chemically 
of simple molecule, contain carbon as well as nitrogen and 
may therefore undergo partial oxidation. They are to a cer- 
tain extent fuel foods, since part of the molecule is oxidized 
to supply heat and energy. The chemical formula of one of 
the simplest amino acids, glycocoll, is CH 2 NH 2 COOH. Other 
amino acids are of larger molecule. 

The protein foods in most common use are meat, fish, milk 
and eggs, although much nitrogen is to be found in the lentils, 
peas and beans, and in such wheat products as bread, and 
macaroni. Enough of this type of food is required to supply 
nourishment for growing or wasted tissue but it has usually 
been found that where man is free to choose his diet to a 
considerable extent there is an excess rather than a deficiency 
of protein. Only in India has a characteristic protein de- 
ficiency been found and here the effects among the members 
of the lower classes, where meat and fish are rare articles of 
diet, include a lessened physical vitality and a dwarfed stature. 
Where protein is taken in excess the carbon and hydrogen 
portion is used as fuel food and the excess of nitrogen is 
excreted through the kidneys in the form of urea. The office 
and professional worker often places a heavy burden on the 
kidneys by making them excrete a large amount of nitrogen 
in only a small amount of water. 

Carbohydrates. — The carbohydrates (sugars and starches) 
are compounds of carbon, hydrogen and oxygen in which 
hydrogen and oxygen are present in the same ratio as in 
water. They are admirable fuel or energy producing foods be- 
cause when they are oxidized or burned in the body they are 



36 hygiene: dental and general 

completely broken down into carbon dioxide and water, both 
of which are easily eliminated waste products, 

Digestion reduces all sugars and starches to simple sugars 
of the C 6 H 12 6 type such as dextrose (glucose or grape sugar) 
and these are the digestive products which pass through the 
walls of the alimentary canal. The absorption of sugars is 
rapid and begins in the stomach. For this reason simple sug- 
ars supply the body with fuel very promptly. This also ex- 
plains why eating sweets a short time before meals takes away 
the appetite. 

Sugar is the form in which carbohydrate is transported 
and used in the body while starch is the more complex storage 
form. The blood usually contains from 0.06 to 0.1 per cent 
sugar and a reserve supply is kept in the liver as glycogen 
or animal starch. The body is free to draw upon this reserve 
when more energy is needed so that the amount of sugar in 
the blood may be increased when fear, anger or other emotions 
press the body for vigorous action. After the sugar content 
of the blood rises to 0.2 or 0.3 per cent glycosuria (the pres- 
ence of sugar in urine) appears. For a man doing physical 
work especially in the cold where heat is lost rapidly a large 
carbohydrate diet is essential and under these conditions it is 
natural for the individual to increase the relative amount of 
carbohydrates in the diet. A man in a sedentary occupation 
does not require so large a quantity of this type of food. 

Fats. — The third type of food passes the walls of the ali- 
mentary canal in the form of soap, glycerine, and fatty acids. 
The fats or hydrocarbons also contain the elements of carbon, 
hydrogen, and oxygen but the proportion of oxygen is less 
than in sugars and starches. Consequently they may be re- 
garded as fuel foods in a more concentrated form since the 
same weight requires more oxygen for combustion and there- 
fore is of greater heat value. Fat is a good reserve food 
since large quantities may be stored in the adipose tissues. 
To a large extent it is interchangeable in the diet with sugars 



HYGIENE OF NUTRITION 37 

and starches. The production of large quantities of butter 
fat by the cow, which subsists upon a protein and carbohy- 
drate diet, is an excellent demonstration of the ability of the 
animal body to synthesize fats from these other types of food. 
Inorganic Salts. — The fourth group of body foods con- 
tains inorganic salts of sodium, calcium, potassium, sulphur, 
iron, and phosphorus. The salts of calcium are important in 
forming the hard structure of bone and the dentin of the teeth. 
The chlorine of common salt is used in the production of 
hydrochloric acid for gastric digestion. Iron, sulphur, and 
phosphorus are important constituents of the more vital tis- 
sues. 

These salts are obtained in organic or inorganic form but 
are most readily usable in the body when secured as organic 
salts from plant and animal structures. There is at present 
a tendency among physicians to prescribe the salts needed by 
the body in the organic form in which they are found in foods 
rather than in the inorganic form as they are frequently com- 
bined in drugs. Most proteins are found associated with 
some of these minerals. Lettuce is particularly rich in potas- 
sium. Calcium is very abundant in milk. Phosphorus is 
plentiful in meats and egg yolk. With the exception of iron 
the salts in milk (as found in the ash) correspond not with 
those in the blood but with the ash obtained from the whole 
young animal. Iron is very plentiful in meat, yolk of egg 
and in spinach, apples and asparagus. 

Vitamines. — The so-called vitamines, which have been 
classified here as the sixth group of food substances, are of 
a chemical composition which is still unknown. It is evident 
however, that there are two types of substances, some soluble 
in water and some soluble in fat, which are essential to the 
diet in preventing the onset of certain so-called dietary dis- 
eases. They are found in the husks of natural grain, in vege- 
tative tissues like the leaves of green vegetables, and in butter, 
olive oil, and other natural fats. 



38 hygiene: dental and general 

Dietary Diseases. — A dietary deficiency in these substances 
has been established as a cause of beri-beri, rickets, and scurvy 
and it is thought to be the cause of pellagra. 

Beri-Beri is found in Asia among the people who make a 
large part of their diet of polished rice. It is characterized by 
progressive emaciation, loss of weight and of strength. There 
is neuritis, the inflammation of the nerve trunks being followed 
by degeneration resulting in prostration and frequently in 
death. This disease has been induced experimentally by feed- 
ing birds upon polished rice. The birds showed a typical 
polyneuritis with inactivity, loss of weight, and muscular 
contraction. But when fed with an aqueous extract of rice 
bran the birds immediately recovered. In the same manner 
the disease among human subjects has been stamped out by 
using unpolished rice or by introducing a mixed diet. 

Pellagra, a somewhat similar disease, has been found to be 
most common in countries where corn is the chief article of 
diet and where the husk and germ of the grain are removed 
before grinding. The disease is characterized with erythema, 
digestive- and nervous disturbances. Sometimes cachexia, 
muscular weakness and insanity develop. The evidence is 
not as clear in this case but here again the disease seems to 
be produced by a diet of the pure starch of a cereal food to 
the exclusion of the leafy and vegetative tissues which con- 
tain the needed vitamine. 

Scurvy, which is produced by a lack of fresh foods in the 
diet, was a common disease upon ships in the days before it 
was possible for them to carry a larder stocked with fresh, 
canned, or cold storage vegetables and meat. It has now 
largely disappeared. The introduction of the potato was an 
important factor in driving the scourge from Europe, by in- 
creasing the quantity of fresh vegetables eaten. Infantile 
scurvy occasionally results from the exclusive use of pasteur- 
ized milk. The feeding of a small quantity of orange juice, 
however, is a preventive and a cure. The characteristics of 
this disease are weakness, soreness of the gums, loosening of 



HYGIENE OF NUTRITION . 6\) 

the teeth, bleeding from the mucous membrane and friability 
of the bones. 

Rickets is a dietary disease which results in the absence of 
normal growth in the child and which is apparently due to 
the lack of one or more vitamines. The symptoms include 
restlessness, fever, profuse sweating, emaciation and altera- 
tion in the growth of the bones. The head becomes bulky, 
the sides of the thorax flatten, the sternum projects and fre- 
quently there is a bending of the spinal column and long 
bones. 

Our knowledge of these subjects, although incomplete, has 
given an added importance to the place of fresh vegetables 
and natural fats in the diet of children. The presence of 
these substances is essential for health although the vitamines 
themselves are needed only in minute quantities. 

Balanced Diet. — Proper nutrition not only demands that 
these six kinds of foods be secured but that they be secured 
in proper proportions. This proportion may be judged 
roughly from the composition of milk which is the perfect 
food prepared by nature for young infants. Human milk 
contains approximately 2%% protein, Sy 2 % fat, 6%% sugar 
and 0.25 % inorganic salt. We find therefore that water 
makes 86% of the infant's diet. Vitamines are also present 
in mother's milk but as in any diet in analytically negligible 
quantities. 

The quantity of the three important types of food which 
are necessary for a normal individual has usually been com- 
puted on the basis of the number of calories necessary for 
the individual. A calorie is the amount of heat required to 
raise a kilogram of water one degree centigrade. It is pos- 
sible to measure the energy output of the body in calories and 
to determine the heat energy in the same way. Each gram 
of protein, fat, and carbohydrate material when oxidized 
yields respectively 4.1, 9.3 and 4.1 calories. 

It is found that the energy requirement varies according 
to the age and size of the individual and the amount of physi- 



40 



HYGIENE: DENTAL AND GENERAL 



cal work performed. The child needs more protein food than 
the adult because new tissue is being produced. Murlin 
points out that ice cream represents the proper proportions 
for adults since it is milk plus sugar and fat, the protein being 
diluted. The child also needs relatively more fuel food for 
the work done because the small body has more surface to 
the unit weight and the amount of food required varies more 




Fig. 9. — The composition of cow's milk. The bottles are arranged from 
left to right to show the actual amounts of water, sugar, fat, protein and ash 
in a quart of milk. 



directly with the surface of the body than with the weight 
of the body. 

Men doing muscular work usually secure 3,500 calories or 
more in their daily ration. People of sedentary occupation 
find something less than 2,500 to be sufficient. The following 
table taken from Stiles' Human Physiology gives a suitable 
average food combination for the sedentary individual: 



HYGIENE OF NUTRITION 



41 



Protein 

Fat 

Carbohydrate 

Total 



75 grams or 300 calories 

50 grams or 465 calories 

375 grams or 1500 calories 



2265 calories 



Another way to estimate the food requirement in protein, 
carbohydrates, and fat would be to state the amount of some 
well-known food necessary to provide a sufficient quantity of 
each. If all the protein in the day's diet were to be secured 




Fig. 10. — Portions of different foods each yielding approximately 100 calorics 
of heat energy. They include: an ordinary serving of beans, 3 large lumps of 
sugar, 1 large banana, 11 double peanuts, 1 large egg, 1 potato, 1 chop, 2 slices 
of bread, 1 orange, 2 apples, % of a glass of milk, 1 pat of butter, and an average 
serving of oatmeal. 



from lean beefsteak, all the fat from butter, and all of the 
carbohydrate from rice the individual would need to eat ap- 
proximately the following quantities of these foods in order 
to secure the gram or caloric requirement mentioned above : 

Beefsteak % lb. (375 gr.) 

Butter y s lb. ( 59 gr.) 

Rice 1 lb. (475 gr.) 



42 hygiene: dental and general 

The Varied Diet. — The whole tendency of recent dietary 
study has been to show that variety in diet is necessary. A 
variety of proteins is desirable because each protein is made 
up of a different combination of amino acids, which we 
have called the building blocks; and in order to be sure to 
include in the food all of the amino acids needed by the body 
many different proteins should be eaten. Again we have seen 
that fresh vegetables, leafy tissues, meats and natural fats 
contain "vitamine" substances which are little known chem- 
ically but which are necessary for a proper balancing of the 
diet. 

Furthermore, man must choose a reasonable amount of hard 
foods in order to exercise the jaw and preserve the teeth. A 
certain amount of bulk must also be secured to furnish a stim- 
ulus for peristalsis in the intestines and maintain the normal 
activity of the bowels. This is secured by eating fruit, vege- 
tables and other bulky foods poor in nutritive value. 

2. DIGESTION 

Good digestion is something more than the mere swallowing 
of the proper number of grams of the various kinds of food 
each day. To get the best results the food must be appetizing, 
the person must be in the proper mental state, the food must 
be eaten in suitable fashion, and bodily activities must not 
seriously interfere with digestion. 

Digestion and the Emotions. — The recent work of Dr. Can- 
non upon the emotions (Bodily Changes in Pain, Hunger, 
Fear and Rage, by "Walter D. Cannon; D. Appleton & Co., 
1915) has shown us clearly the importance of proper psychic 
conditions in normal digestion. Nowhere else is there such a 
good statement of the facts at hand. Commenting upon the 
previous work of Pawlow with dogs Cannon says: 

By the use of careful surgical methods he was able to make a side 
pouch of a part of the stomach, the cavity of which was wholly separate 
from the main cavity in which the food was received. This pouch was 
supplied in a normal manner with nerves and blood vessels and as it 



HYGIENE OF NUTRITION 43 

opened to the surface of the body, the amount and character of the 
gastric juice secreted by it under various conditions could be accurately 
determined. * * * In some of the animals thus operated upon an 
opening was also made in the esophagus so that when the food was 
swallowed, it did not pass to the stomach but dropped out on the way. 
All the pleasures of eating were thus experienced, and there was no 
necessity of stopping because of a sense of fullness. This process was 
called "sham feeding. " The well-being of these animals was carefully 
attended to, they lived the normal life of dogs, and in the course of 
months and years became the pets of the laboratory. 

By means of sham feeding Pawlow showed that the chewing and 
swallowing of food which the dogs relished resulted, after a delay of 
about five minutes, in a flow of natural gastric juice from the side pouch 
of the stomach — a flow which persisted as long as the dog chewed and 
swallowed the food, and continued for some time after eating ceased. 
Evidently the presence of food in the stomach is not a prime condition 
for gastric secretion. And since the flow occurred only when the dogs 
had an appetite, and the material presented to them was agreeable, the 
conclusion was justified that this was a true psychic secretion. 

Other experiments upon dogs have shown that merely the 
sight or smell of a favorite food will start the pouring out of 
the gastric juice. Analogy teaches us that good cookery not 
only makes our mouth water but it makes our stomachs water 
as well. This initial psychic secretion of gastric juice is im- 
portant because the continuance of its flow during digestion 
is brought about by the reaction of its acid or digestive pro- 
ducts upon the mucous membrane of the duodenum. 

The saliva produced when the mouth waters not only starts 
the digestion of starches but it also assists in enabling us to 
taste our food, for materials are tasted only when they are 
dissolved. 

To quote further from Dr. Cannon's excellent description: 

The conditions favorable to proper digestion arc wholly abolished 
when unpleasant feelings such as vexation and worry, or great emotion 
such as anger and fear, are allowed to prevail. This fact, so far as the 
salivary secretion is concerned, has long been known. The dry mouth 
of the anxious person called upon to speak in public is a common in- 
stance; and the "ordeal of rice, " as employed in India, was a practical 
utilization of the knowledge that excitement is capable of inhibiting the 
salivary flow. When several persons were suspected of crime, the con- 



44 HYGIENE: dental and general 

secrated rice was given to them all to chew, and after a short time it 
was spit out upon the leaf of the sacred fig tree. If anyone ejected 
it dry, that was taken as proof that fear of being discovered had 
stopped the secretion, and consequently he was adjudged guilty. 

What has long been recognized as true of the secretion of saliva has 
been proved true also of the secretion of gastric juice. For example, 
Hornborg was able to confirm in his little patient with a gastric fistula 
the observation by Pawlow that when hunger is present the mere seeing 
of food results in a flow of gastric juice. Hornborg explained the 
difference between his and Pawlow 's results by the different ways in 
which the boy and the dogs faced the situation. When food was shown, 
but withheld, the hungry dogs were all eagerness to secure it, and the 
juice very soon began to flow. The boy, on the contrary, became vexed 
when he could not eat at once, and began to cry; then no secretion ap- 
peared. Bogen also has reported the instance of a child with closed 
esophagus and gastric fistula, who sometimes fell into such a passion in 
consequence of vain hoping for food that the giving of food, after the 
child was calmed, was not followed by any flow of the secretion. * * * 

The studies of Bickel and Sasaki confirm and define more precisely this 
inhibitory effect of strong emotion on gastric secretion. They observed 
the inhibition on a dog with an esophageal fistula, and with a side pouch 
of the stomach, which, as in Pawlow 's experiments, opened only to the 
exterior. In this dog Bickel and Sasaki noted, as Pawlow had, that 
sham feeding was attended by a copious flow of gastric juice, a true 
psychic secretion, resulting from the pleasurable taste of the food. In 
a typical instance the sham feeding lasted five minutes, and the secre- 
tion continued for twenty minutes, during which time 66.7 cubic centi- 
meters of pure gastric juice were produced. 

On another day a cat was brought into the presence of the dog, 
whereupon the dog flew into a great fury. The cat was soon removed, 
and the dog pacified. Now the dog was again given the sham feeding 
for five minutes. In spite of the fact that the animal was hungry and 
ate eagerly, there was no secretion worthy of mention. During a period 
of twenty minutes, corresponding to the previous observation, only 9 
cubic centimeters of acid fluid were produced, and this was rich in 
mucus. * * * 

On another occasion Bickel and Sasaki started a gastric secretion 
in the dog by sham feeding, and when the flow of gastric juice had 
reached a certain height, the dog was infuriated for five minutes by 
the presence of a cat. During the next fifteen minutes there appeared 
only a few drops of a very mucous secretion. * * * 

Eecently Oechsler has reported that in such psychic disturbances, as 
were shown by Bickel and Sasaki to be accompanied by suppressed se- 



HYGIENE OP NUTRITION 45 

cretion of the gastric juice, the secretion of pancreatic juice may be 
stopped, and the flow of bile definitely cheeked. All the means of bring- 
ing about chemical changes in the food may be thus temporarily abol- 
ished. 

Dr. Cannon describes most interestingly his own experi- 
ments which show that the excitement in pain, fear and rage 
also prevent the normal contractions of the stomach and in- 
testines. 

Even indications of slight anxiety may be attended by complete ab- 
sence of the churning waves. In a vigorous young male cat I have 
watched the stomach for more than an hour by means of Roentgen rays, 
and during that time not the slightest beginning of peristaltic activity 
appeared; yet the only visible indication of excitement in the animal was 
a continued quick twitching of the tail to and fro. 

Physicians who treat great numbers of digestive disorders 
frequently receive a clinical history of indigestion with symp- 
toms of heaviness in the stomach after eating, as though the 
food failed to pass on to the intestines. Such a case exhibits 
an increasingly aggravated condition. This type of nervous 
or emotional indigestipn in specific cases has been shown to 
be definitely related to unfavorable mental states. The ac- 
companying diagram shows the way in which the autonomic 
nervous system reaches and affects the various parts of the 
body. 

It should be added here that the secretion of adrenalin and 
the increase of the sugar content of the blood are important 
and complicating factors. Not only is digestion completely 
inhibited by the stronger emotions but the blood and muscles 
are supplied with more fuel and the circulatory and nerv- 
ous systems are toned up to enable man to exert his utmost 
physical strength as he was usually called upon to do during 
his more primitive existence and during the long period of 
evolution. 

The Hygiene of the Emotions.— Certain conclusions inev- 
itably follow. Digestion ensues much more readily if the food 
eaten is appealing in sight, odor and taste. Among people 
who, because of illness or for some other reason have a dainty 



46 



HYGIENE: DENTAL AND GENERAL 




Fig. 11.— Diagram showing the most important distributions of the Autonomic 
Nervous System. One-half of the brain and spinal cord is represented at the 
left. The preganglionic fibers of the Autonomic Nervous System are in solid 
lines; the postganglionic in dash lines. The cranial, cervical, dorsal, lumbar, 
and sacral divisions of the nervous system are indicated by the letters Cr, Ce, 
D, Lu, and Sa, respectively. The organs indicated as affected by the emotions 
include the lachrymal glands, the pupils of the eyes, the salivary glands, heart, 
hair, superficial arteries, sweat glands, adrenal bodies, stomach, intestines, colon, 
bladder, and genitals. (After Cannon.) 



nYGIENE OF NUTRITION 47 

appetite special care in these particulars is very important. 
It is also clear that the forced feeding of children, the un- 
necessary punishment of children at the table, and feeding 
immediately after the child has been in a passion are all un- 
hygienic. Among adults it is equally important that the 
meal should be pleasant and free from anxiety, worry and ill- 
feeling. Otherwise a vicious cycle will be set up and the 
man who begins by worrying at his meals or thinking in- 
tensely upon the problems of his work will set up a mild in- 
digestion which will in turn lower his efficiency, aggravate 
his work by depleting his physical condition and initiate him 
into the unstable and unenviable fraternity of neurasthenics. 

"Enjoy your food" is an excellent maxim. Enjoy your 
meal, the surroundings, the company and the food. Choose 
food which you will enjoy eating and eat slowly. If food is 
eaten under proper conditions it is much more likely to be 
eaten properly. 

Mastication. — The digestion of starches and sugars and 
the preparation of these substances for absorption is begun 
in the mouth. If these foods are swallowed without proper 
chewing and the addition of saliva their normal digestion is 
impossible. 

Important beginnings of protein digestion take place in 
the stomach by the action of the peptic secretion from the 
walls of the stomach and these are carried further by the 
action of the pancreatic juice and other fluids. These fluids 
must act upon the exposed surfaces of foods and therefore if 
a piece of meat the size of a marble is cut into particles the 
size of coai'se sand by proper chewing, the surface area avail- 
able for digestive action is increased many fold. The prin- 
ciple adopted by Horace Fletcher, who selected foods which 
appealed to his appetite and chewed all food till it was prac- 
tically liquid in the mouth, is sound but more difficult of suc- 
cessful practice for the poor and busy man than it was for 
Mr. Fletcher. 



48 HYGIENE: DENTAL AND GENERAL 

Water With Meals. — There has been much discussion about 
the advisability of drinking quantities of water with the 
meals. There seems to be no reason why water taken with the 
meals should be injurious unless it is used to wash down dry 
food in order to save the individual the trouble of chewing 
or unless it is taken at a low temperature and in such quan- 
tities as to cool the stomach and slow up the action of the 
secretive tissues of the stomach wall. 

Rest After Eating. — In experiments recorded above Paw- 
low shows that the secretion of gastric juice lasted for twenty 
minutes after the end of a five minute period of sham feeding. 
Bickel has also shown, in the case of a girl with a closed 
esophagus and gastric fistula, that gastric secretion continued 
active for some time after eating even when no food had 
entered the stomach. We have also seen that the effects of 
the unpleasant emotions and mental states are sufficient to 
inhibit the secretion of digestive juices after the process is 
once started. For these reasons and because of the with- 
drawal of blood from the digestive tract to the muscular 
organs in the case of hard manual labor we may conclude that 
an after-lunch rest period, postponing for at least one-half 
hour the return to active labor, is highly desirable. 

3. ASSIMILATION 

Assimilation Denned. — The processes of nutrition which 
take place after the food has been absorbed by the walls of 
the digestive tract and taken into the circulation are chiefly 
the functions of the absorption and combustion of the food 
material in the tissues and the elimination of waste from the 
body. These processes include the use of the gaseous food, 
oxygen, and the elimination of the chief end products of com- 
bustion, water, carbon dioxide and urea. Nitrogen is elimin- 
ated through the kidneys, in the form of urea, carbon dioxide 
through the lungs, and water through the lungs, kidneys and 
skin. 



HYGIENE OF NUTRITION 49 

Oxidation. — Apparently assimilation is not impaired by 
a lack of oxygen due to poor ventilation. As we shall see in 
describing ventilation, the injurious effects of poor air are 
not due to the chemical content of the air but to an entirely 
different set of factors. The supplying to the tissues of this 
all important gaseous food depends much more upon proper 
breathing and suitable exercise. These matters will be con- 
sidered in more detail under the hygiene of action. 

Eliminating- the Body Wastes. — The elimination of urea 
is made easier by limiting the protein diet so as to avoid an 
excess of nitrogen for elimination by the kidneys and by 
drinking large quantities of water in order to reduce the con- 
centration of the urine. It has been shown that the action 
of the kidney in withdrawing the salts of urea from the blood 
and combining them in a much more concentrated form in 
the urine involves definite energy consumption. 

The evacuation of the bowels is mainly the elimination 
from the body of substances which have never passed through 
the walls of the alimentary canal since the secretions which 
are thrown into the digestive tract constitute but a small 
part of the feces. But we should not neglect to reaffirm the 
importance of so regulating the diet and the habits that de- 
fecation may be regular in order that the material in the 
rectum and lower bowel may not become inspissated and ab- 
sorbed to such an extent that the blood is loaded with these 
poisonous waste proteins and the vitality of the individual 
temporarily impaired. 

Autointoxication. — We have seen that the emotions may 
so interfere with digestion that the process is not properly 
commenced or if underway it is brought to an abrupt stop. 
When this occurs food may remain in the stomach for many 
hours instead of being passed on to the intestine. The bac- 
teria, which are always present in the digestive tract in count- 
less numbers, are especially active when digestion and normal 
absorption is delayed so that the fermentations which they 
set up in the intestine produce gas and cause pain. Under 



50 HYGIENE: DENTAL AND GENERAL 

normal conditions the nitrogenous food is largely absorbed 
before the material reaches the colon bnt if digestion has not 
been sufficiently completed these proteins do reach the large 
intestines and undergo putrefaction with the consequent pro- 
duction of poison which will be absorbed into the blood and 
produce the ill effects of autointoxication. 

The signs of beginning or transient autointoxication are 
drowsiness, inertia, headache and a feeling of fatigue. If it 
is long persistent nervous depression, hardening of the ar- 



il \itr it ional 
Disturbance 



Unhappy Mental State Delayed Absorption. 




Increased Bacterial Action. 



Absorption of abnormal products 
of bacterial action. 

Fig. 12. — The worry-autointoxication cycle. 

teries, anemia, and arthritis may result. The body will re- 
cover from a single attack of autointoxication but it may be 
readily seen that long continued grief or anxiety may produce 
a chronic condition which in turn would increase the nervous 
trouble setting up a vicious cycle. 

Overeating as well as the emotions will cause autointoxi- 
cation and it is possible that the slightly excessive consump- 
tion of food may in the long run produce injurious effects. 
Fortunately for the individual greatly overloading the stom- 



HYGIENE OP NUTRITION 51 

aeh is likely to be followed by a mild diarrhea. In the case 
of autointoxication the occasional use of a cathartic is bene- 
ficial but it should not be used too often. Moderation and 
temperance in eating especially in the eating of protein foods 
is most important. The drinking of sour milk or the regular 
ingestion of lactic acid bacteria is a measure aimed to prevent 
the putrefaction associated with autointoxication by substi- 
tuting lactic acid fermentation as the dominant type of bac- 
terial action in the alimentary canal. 

Constipation or the slow movement of food along the in- 
testinal track may or may not be associated with autointoxi- 
cation. Its seriousness is overemphasized in the ever present 
advertisements for cathartics, but the condition is harmful 
and should be avoided by the use of plenty of water, by eating 
"roughage" such as fruit and vegetables and by suitable 
exercises. A habit of at least one movement a day at a 
regular time should be established. The habitual use of ca- 
thartics or enemas should not be encouraged. 

Food Poisoning. — The newspapers frequently recount 
cases of "ptomaine poisoning" in which persons suffer from 
extreme pain, diarrhea, and frequently from forcible vomit- 
ing, coupled with a high fever and extreme prostration. Pto- 
maines are supposed to be poisonous substances produced by 
the bacterial decomposition of nitrogenous food under certain 
conditions. It is lately much less common to hear of ptomaine 
poisoning and many cases which have been so reported have 
been found upon investigation to be due to bacterial infection. 
In fact the existence of specific ptomaines is in question. Re- 
cent experiments upon the quality of canned foods have com- 
pletely failed to disclose the presence of ptomaines or other 
poisons. 

Certain people are poisoned by particular foods such as 
pears, eggs, lobsters, etc. This type of poisoning is hard to 
understand but it may be a type of anaphylatic reaction as 
suggested in the chapter on Immunity. 



52 HYGIENE: DENTAL AND GENERAL 

Obesity. — The tendency to become overweight is no doubt 
constitutional although of course it is true that adipose tissue 
can only be acquired by the continued consumption of more 
fuel than is used by the body. 

There are two ways to combat overweight, by reducing the 
amount of food or by increasing the oxidation. When we are 
not eating we are losing weight at the rate of about one ounce 
an hour. Fasting will reduce weight but it is extremely un- 
pleasant. Sometimes drugs are given which destroy one's 
appetite but they too are likely to be unpleasant and to injure 
digestion. The oxidation of food may be increased by ex- 
ercise but, unfortunately for the person who is trying to re- 
duce, exercise is followed by an increased appetite and a 
greater consumption of food. 

The use of a diet high in protein is sometimes recommended. 
This decreases the amount of food eaten because protein 
quickly satisfies hunger and also accelerates the process of 
oxidation. This procedure always places too heavy a burden 
upon the kidneys ; and perhaps a better and more consistent 
plan is to substitute, in so far as possible, coarse and bulky 
foods like fruit and vegetables for the fuel foods like sugar, 
starches and fats. In this way hunger, can be satisfied with- 
out taking too much nutritive material. 

Under-Eating. — Common and bothersome as are the prob- 
lems of overweight cases of under-eating are perhaps more 
serious and more frequent. Many people suffer the loss of 
physical and mental vigor because through carelessness in 
their eating habits or lack of means, they fail to secure the 
food that they should have. Women, particularly, often fail 
to secure suitable and nourishing food because of the expense 
or because of the trouble of preparing food for themselves 
when they are alone. 

Such a person is in many respects the exact opposite of the 
individual who is overweight. The underfed person drags 
himself about — underweight, pale, sensitive to cold, morose, 
querulous, and pessimistic. He sleeps lightly and works with- 



HYGIENE OF NUTRITION 53 

out enthusiasm and without surplus energy. The overfed 
person is perhaps not very diligent but he is cheerful, opti-^ 
mistic, of ruddy countenance, and a heavy sleeper. To secure 
the golden mean in diet is greatly to be desired but perhaps it 
is better to err slightly on the side of plenty. 

CONCLUSIONS 

Many factors are involved in the proper regulation of the 
diet. The protein must be applied in suitable quantity and 
variety. The quantity of the fuel foods must be adjusted to 
the kind of work being done. Plenty of water is essential. 
The necessary inorganic salts must be secured from various 
sources and vitamine substances must be provided. The emo- 
tions must not be allowed to impair the digestion and proper 
habits of eating should be acquired. 

Every person should study himself and learn what foods 
best agree with him. He should experiment to find the best 
arrangement for hours and types of meals. In general men 
doing mental work find that they can do best when the break- 
fast and lunch are not too heavy and the hearty meal is eaten 
at night. Lunch particularly should be light, if work is to 
be done early in the afternoon. Many but not all people 
work best on a light breakfast. But in all these things per- 
sonal habits, bodily constitution, and daily schedule are im- 
portant and although there are some general rules every per- 
son must learn what best agrees with him. 



CHAPTER III 

THE HYGIENE OF ACTION 

Two Kinds of Bodily Activity .—Independent activity of 
the organism begins with birth and ends only with death. 
Even the person who avoids physical evercise carries on a 
variety of muscular activities including the beating of the 
heart, breathing, and the functions of walking, riding, sitting, 
standing, eating, gesturing, talking, etc. Some of these activi- 
ties are involuntary and others are so simple as not to require 
careful attention, but in all these activities and in a con- 
trasted group of activities which we may term active physical 
exercise, there arise certain problems of hygiene. 

EXERCISE 

Voluntary muscular activity or exercise will be first con- 
sidered. The professional man or the individual engaged in 
a sedentary occupation will do well to give careful attention 
to the beneficial effects of regular and proper exercise and to 
the dangers incident to its neglect. Exercise is more essential 
to his happiness than mental development is to the happiness 
of a man employed in active physical labor. 

It is a pernicious fallacy to regard healthful and vigorous 
exercise as an unnecessary burden in the day's work merely 
because the changed living conditions since the days of our 
forefathers have rendered mental activity the usual, and phys- 
ical activity the unusual mode of life for the professional, 
business and clerical classes. Especially among the intellec- 
tually inclined there is danger that the desire for a good phys- 
ical condition of the body may stop with the envy of those 
who possess such a body or with an attempt to secure the same 
stimulation in another way or by an easier road, in using mas- 

54 



HYGIENE OF ACTION 55 

sage, alcoholic stimulants, drugs and patent medicines, instead 
of learning the real delight and joy of a proper physical 
condition resulting from well-directed exercise. 

What Exercise Does for the Body. — Briefly, what are the 
real and actual effects of regular physical exercises upon the 
body? In the first place it is a most important stimulus to 
the circulation of the blood and the lymph. The movement 
of the muscles and other organs exerts a massaging action on 
these two streams in the capillaries and lymph spaces ; and the 
increased respiration exerts a suction upon the venous blood 
into the great veins near the heart by the same bellows-like 
action with which air is drawn into the lungs. This increased 
breathing is also important to the lungs themselves in filling 
air spaces which under normal conditions may not be used, 
and particularly in inflating the apical regions of the lungs. 

The increased bodily activity increases the oxidation going 
on in the body. The extent of this action is shown by the 
fact that the output of carbon dioxide is increased from three 
to ten times by muscular activity whereas the digestive process 
only increases its output one-fifth. This carbon dioxide is 
thrown off through the lungs. Water is another waste pro- 
duct and the skin is cleared by the generous excretion of the 
sweat glands and the consequent softening of the horny 
layers. 

The most generally obvious aspect of exercise is the build- 
ing up of the general muscular system which constitutes two- 
thirds of the bulk and weight of the body. Muscle fibrils 
increase in size when used but when unused they decrease 
until hardly more than the connective tissue remains of what 
should be a strong and vigorous muscle. Nor is this unim- 
portant for the man of sedentary occupation, because for 
everyone there are emergencies which must be met by unusual 
physical energy. Running for a street car, running upstairs, 
cr sudden emergencies which occur in the professional activity 
of the dentist or physician, require physical energy and often 
considerable muscular strength. This need of reserve strength 



56 HYGIENE: dental and general 

is especially important in the case of the heart which like 
the skeletal muscles is built up and strengthened by proper 
physical exercise. In the emergencies cited above and in 
certain diseases like pneumonia it is primarily important that 
the heart is sufficiently strong to withstand the strain. In 
fact, in disease the strength of the heart often determines the 
question of life or death. 

But the other internal organs also gain vastly from physi- 
cal exercise. The viscera are relieved from serious internal 
congestion which is likely to take place in the body of a 
sedentary individual and which predisposes the internal 
organs to diseased condition. The stagnation of the blood 
and lymph in the large vessels running from the digestive 
organs to the heart interferes with digestion, circulation, and 
the sense of physical well being. Digestion itself is aided by 
the increased peristalsis produced by the churning activities 
of these organs and by the increased use of the abdominal 
muscles. 

To anyone who has learned to enjoy physical exercise it 
is not necessary to say that the general toning up of the bodily 
activities, the improvement of the circulation and all the at- 
tendant changes mentioned above, produce a beneficial effect 
on the mental tone. Of equal importance is the effect upon 
the heat-regulating mechanism. Muscular activity opens the 
small blood vessels of the muscles and the region near the 
skin and contracts the blood vessels of the internal viscera. 
It is upon our ability to make these changes that we rely in 
large part for our bodily adjustments to changes of temper- 
ature. A trained and adaptive heat-regulating mechanism 
is therefore essentially important to the general health. 

In summarizing the foregoing we may list the beneficial 
effects of muscular exercises as (1) an aid to circulation, 
(2) an aid to oxidation, (3) an aid in the elimination of 
waste, (4) clearing the skin, (5) strengthening the muscular 
system, (6) aiding digestion, (7) improving the mental tone, 
(8) relieving internal congestion, (9) strengthening and en- 



HYGIENE OF ACTION 57 

larging the lungs, (10) strengthening the heart, and (11) im- 
proving the heat regulating mechanism. 

Types of Physical Exercise. — The type of physical exer- 
cise which one may take depends upon his physical fitness, age 
and inclination. It is far better to build a good body in 
youth and to maintain its efficiency throughout life, but it is 
never too late too begin bodily improvement provided this is 
done in a sane and proper manner. To allow a horse to re- 
main in the stable for weeks then drive it a hundred miles in 
a day would spoil the animal; yet many people expect the 
human mechanism to accomplish similar feats, in rare and im- 
moderate exercise. Some who rarely exercise go to excess be- 
cause when the opportunity to exercise offers itself there is a 
joyous outlet of pent-up energy and the individual does not 
realize (at least until he tries to get out of bed the next morn- 
ing) that an unused muscular system has its limitations. 
Others overdo because they have once been athletic and do 
not realize that absence from regular exercise has depleted 
their powers of endurance. 

The first requisites of the most helpful exercise are that it 
should be regular, enjoyable, and adapted to the individual. 
The person who religiously resolves to attend the gymnasium 
at least three times a week finds that after the second or third 
week it begins to pall on him. If he is taking routine exer- 
cises, he goes through a definite set of mental processes. As 
the hour approaches for him to enter the gymnasium he has 
a feeling of dislike for the task and is sure that he would 
prefer continuing his office activities. Through moral force 
however he persuades himself to go, and after completing his 
exercise and being refreshed by a shower bath he feels so 
invigorated that he firmly resolves to enter the gymnasium 
six times a week instead of three. Yet the same compulsion 
must be exercised the very next day if he is to resume his 
exercises. 

The strengthening of the physical and mental fiber will 
certainly repay this individual if he persists in the regular 



58 HYGIENE: DENTAL AND GENERAL 

routine of exercise. Gymnasia are invaluable assets in the 
life of the city. If, however, the exercise can be varied so 
that the man takes a delight and looks forward to the time 
when he will have an opportunity to exercise, much is accom- 
plished. With some individuals the innovation of athletic 
games accomplishes this result. Such a man takes a keen joy 
in a contest; in making himself expert and proficient in a 
particular way. Still another type of mind dislikes any ac- 
tivity which is not productive. Hunting, fishing, exploring, 
training horses, gardening, carpentering, etc., all appeal to 
such a man and fortunate is he who can elect his ideal exer- 
cise from this group. These activities, however, are not al- 
ways available to the occupant of a five room flat ; so perhaps 
we should say most fortunate is the man who can become fond 
of any of the types of physical exercises mentioned. 

Rhythm in Exercise. — More should be said about the na- 
ture of the exercise itself. It should involve rhythmic and 
not continued muscular contraction. A type of exercise like 
tennis, baseball, or football is a much more general and in- 
vigorating bodily exercise than the mere lifting of heavy 
weights. The exercise should be such that free play is granted 
to the various parts of the body. The lungs should be free 
to expand to their fullest extent, and the movements of the 
trunk should be free and easy. That exercise is most helpful 
which is sufficiently varied to call into use a great number of 
the muscles of the body. Above all things the exercise should 
be reasonably vigorous. 

Walking. — Walking, which is an excellent exercise and 
available to everyone, should never be confused with loitering 
or strolling. Fast walking in the open, especially in the 
country, is invigorating, restful and has the added advantage 
of making the man interested in his surroundings and in the 
wonders of the natural world which he was meant to enjoy. 
Mere strolling even though it be in the open is not proper 
exercise and is tiring rather than restful. Air is good and 
essential but the mere breathing of fresh air cannot take the 
place of physical exercise. 



HYGIENE OF ACTION 59 

ORDINARY BODY ACTIVITIES 

The other phase of the Hygiene of Action, which we men- 
tioned in the beginning of this discussion, concerns the proper 
use of the body in the ordinary affairs and conduct of life. 
This involves also the matter of figure, bodily shape, and 
physical force; because these depend upon the proper coord- 
ination and balance of the muscular system. 

Figure. — Good figure and proper carriage are important 
not only in the personal appearance of the individual, directly 
affecting his personality and the estimate set upon his ability 
by the casual observer; but they are also important to health 
as deformities injure and restrict adjacent organs. The body 
is largely made up of opposing sets of muscles which tend to 
move the various parts in the opposite directions like the flexor 
and extensor muscles of the lower leg or arm. Similar sets of 
muscles alter the position of the neck, the chest, the back and 
the jaw. We shall see how the improper use of particular 
muscles may distort the normal figure of the body. This is 
particularly noticeable respecting the shoulders, the neck, the 
back, the abdomen and the feet. 

Round Shoulders. — Round shoulders have become so com- 
mon among large groups of sedentary workers that there is 
danger that we may conclude that they are normal. The 
round-shouldered individual himself is likely to feel that he 
has assumed an abnormal position when he straightens up. 
When straight he looks unnatural merely because he is not in 
his habitual or customary position. It is only when we look 
at the erect posture of a child of three or four years or the 
bearing of the well trained soldier that we realize how odious 
is round-shoulderedness compared with the natural contour. 

This condition is brought about by drawing the shoulders 
forward through the contraction of the muscles of the chest 
and the disuse of the muscles of the back so that finally the 
muscles become set in this position with the chest muscles 
contracted and the back muscles relaxed leaving the shoulders 
in a forward position, cramping the upper part of the chest 



60 



HYGIENE: DENTAL AND GENERAL 



and limiting the breathing. This deformity is brought about 
by a careless attitude at the desk or by leaning forward over 
one's work, and the individual must develop consciousness of 
physical position in order to avoid incorrect posture. Cor- 
rective exercises, in consciously throwing the shoulders back 
with the arms widely extended to one side or in raising the 
arms above the head at the same time drawing a deep breath 
and dropping the arms slowly during the period of exhaling, 
keeping the hands well to the rear, are effective in correct- 
ing this condition. 




Fig. 13. — Good (left) and bad (right) postures. The main lines of the body 
are shown in diagram and it is easy to see that the position at the right would 
be much more tiring. (Burgerstein.) 



Carrying the Head Forward. — Another malady which often 
accompanies round shoulders is the fault of carrying the 
head too far forward. The neck becomes accustomed to 
an abnormal position and is no longer erect. This again is 
due to the weakness of the muscles which hold the head 
back, and the set contraction of the muscles which pull 
the head forward. One of the first corrective exercises for 
both these conditions is that of flattening the back against 



HYGIENE OF ACTION 



61 



a straight, perpendicular wall. The individual backs up to 
a door or wall and places himself in such a position that the 
calves of the legs, the hips, the shoulders, and the back of 
the head lie flatly against the wall. This is approximately 
the normal posture and if a man walks away in this position 



TRACINGS MADE DURING EXAMINATION OF 700 HARVARD 
FRESHMEN 





Group A— 7.5% Group B— 12.5% Group C— 55% Group D— 25% 
Fig. 14. — Posture chart showing the result of the examination of Harvard Freshmen. 

Group A. — Good mechanical use of the human body. 1. Head straight above 
chest, 'hips and feet. 2. Chest up and forward. 3. Abdomen in or flat. 4. Back- 
usual curves not exaggerated. 

Group B. — Fairly good mechanical use of the human body. (Note changes from 
Group A.) 1. Head too far forward. 2. Chest not so well up or forward. 3. Ab- 
domen very little changed. 4. Back very little changed. . 

Group C. — Bad mechanical use of the body. (Note changes from Group A.) 
1. Head forward of chest. 2. Chest flat. 3. Abdomen relaxed and forward. 
4. Back curves are exaggerated. 

Group D. — Very bad mechanical use of the body. (Note changes from Group 
A.) 1. Head still farther forward. 2. Chest still flatter and farther back. 3. Ab- 
domen completely relaxed. "Slouchy." 4. Back all curves exaggerated to the 
extreme. (Eee.) 

and maintains it for some time, repeating the exercise ev- 
ery morning he will gradually accustom himself to the 
proper position of the head and shoulders and this position 
will become the natural one. Another way to exercise the 
muscles at the back of the neck is to clasp the hands be- 



62 HYGIENE: DENTAL AND GENERAL 

hind the head and force the head back against their pres- 
sure. 

Spinal Curvatures. — Another common fault in posture is 
the abnormal curving of the spine either laterally or back- 
ward at the region of the thorax or forward at the region 
of the abdomen. This latter is often associated with pro- 
trusion of the abdomen by increase in fat and the relaxing 
of the ventral abdominal muscles. 

The curvature of the back may be prevented in large part 
by the exercise of trying to make oneself as tall as possible, 
holding the back straight and rising on the toes with arms 
extended over the head, stretching the arms and body. The 
objectional "pot belly" condition may be successfully pre- 
vented and largely overcome by such exercises as lying flat 
on the floor or bed with arms folded and raising the feet and 
head alternately. Lateral, curvatures arise from sitting in a 
leaning position and are most common in children who sit- 
improperly at school. 

Deformities of the Feet. — Less conspicuous but none the 
less important deformities are those which are found in the 
feet. In selecting shoes man seems to conclude that nature 
made a mistake in making the foot broad at the toe and he 
endeavors to make it over into a wedge-shaped organ; -while 
woman tries to improve upon nature by walking upon the 
toes and elevating the heels instead of walking upon the 
flat of the foot. If you will observe an infant or small 
child you will find that the toes are flexible and move side- 
ways and backwards and forwards to a great degree. When 
a child walks the toes "dig into the ground." Held in by 
the shoes in later life this early flexibility and the original 
shape of the foot are largely lost. Especially in people who, 
like dentists, are required to remain on their feet for many 
hours a day, do we find painful and harmful foot conditions. 

There is a natural arch running from the heel to the ball 
of the foot and a small reverse arch from the toes to the 
top of the instep. These arches are held in position by a 



HYGIENE OF ACTION 63 

complex group of muscles. If these muscles are not used 
or if they are so bound up that they are not given proper 
free play, the weight of the body, centering in front of the 
heel, tends to break down the arches and produce a condition 
known as flat foot. This defect will be rather prevalent un- 
til common sense rules fashion and people demand proper 
shoes. 

To take proper care of the feet the shoe must be as wide 
as the foot, the heels must be low and broad, the toes and 
uppers of the shoes must be flexible, there must be room 
for activity at the toes of the boot and the foot must be held 
in such a position when walking that it is carried straight 
ahead. In a normal foot the line drawn through the long- 
axis of the great toe should also pass through the heel. 

The foot must be given proper exercise to strengthen the 
muscles of the ball of the foot and the arch. Dig the toes 
into the ground when you walk, practice the ordinary gym- 
nastic exercise of "heels raised, knees bend," thus calling 
the muscles of the foot into play. Do not wear the shoe 
or the garter so tight as to cause congestion of the blood in 
the foot. All of these things are very important in securing 
fair treatment for one of the most abused members of the 
body. 

The public must learn that from the aesthetic standpoint 
a small foot with a pointed toe and high heel is not the ideal 
foot. 

Such is not the foot of the Apollo Belvedere nor that of the Venus of 
Milo. It is simply a deformity, belonging :z\ the same category with the 
constricted waist, and far more harmful to its possessor than the ear 
or nose ornaments of the Hottentot. No hygienic lesson is more im- 
portant than that clothing should fit the body and not the body the 
clothing. — Scdgwiclc. 

Ocular Hygiene. — The proper use of the eyes and ears 
forms an important part in the ordinary activities of life al- 
though somewhat removed from the subject of muscular ac- 
tion. Both of these complicated sense organs require expert 



64 HYGIENE: DENTAL AND GENERAL 

attention if there is anything seriously wrong. Their im- 
portance and their complexity both demand this. We should 
remember that headaches and even the nausea accompanying 
the so-called "sick headache" may be produced by defects 
in the eyes which are perhaps more often congenitally ab- 
normal than any other organ. 

We can do much to take care of the eyes by being careful 
to use a steady and not a flickering light when we read, 
by choosing paper which is dull and not of a glossy finish, 
and by avoiding in so far as possible, the use of any print so 
fine that it is necessary to hold the book less than eighteen 
inches from the eyes. Occasionally the eyes may be rested 
from the work immediately at hand by changing the focus, 
looking out of the window, and focusing the eyes upon some 
distant object. This is merely an act of muscular relaxation 
to prevent the strain which would otherwise be caused by 
the continual focusing of the eyes upon near objects. 

Breathing. — By the process of breathing the blood acquires 
oxygen and discharges carbon dioxide and the body throws 
off moisture. Nearly all of the carbon dioxide produced in 
the body is discharged through the lungs and about one 
pint of water a day is thrown off in this manner. 

The red blood corpuscles are like tiny boats hauling oxy- 
gen from the lungs to the tissues and exchanging it there 
for carbon dioxide which is brought back to the lungs and 
discharged into the air which is being exhaled. But the 
cargo of these boats is never limited entirely, either to C0 2 
or oxygen for both gases are found in considerable quantity 
in either the arterial or the venous blood. It is as though 
our " ships" were always carrying a certain amount of 
each as ballast and .emptying only a part of their compart- 
ments at the lungs and in the tissues. One hundred volumes 
of arterial blood contain about 20 volumes of oxygen and 38 
volumes of carbon dioxide. One hundred volumes of venous 
blood contain about 12 volumes of oxygen and 45 volumes 
of carbon dioxide. It seems that there is always enough 



HYGIENE OF ACTION 65 

of proper "cargo" at either "loading point" for the boat 
to take on its usual load ; for a person can breathe without 
discomfort in air which has so much carbon dioxide that a 
match will not burn in it. On the other hand the rate of 
oxidation is not increased when a person breathes pure 
oxygen. Only when the blood has fallen below standard 
in disease or during extreme exertion does the breathing of 
pure oxygen have any advantage over the breathing of 
normal air. Here it helps to restore the standard of the 
blood. 

The rate of breathing is not affected by the chemical com- 
position of the air. It is controlled by the concentration of 
carbon dioxide in the blood through its effect upon a spe- 
cial regulating nerve center. Exercise, therefore, naturally 
increases the rate of respiration and this is the best way -to 
take breathing exercises. 

When one practices forced breathing he is likely to be- 
come dizzy or faint. The concentration of carbon dioxide in 
the blood is reduced below the point which should be main- 
tained as a stimulus to the nervous tissues. The most imme- 
diate effect is upon the breathing center which ceases to send 
out the necessary stimuli with the result that breathing is 
stopped or slowed down until sufficient carbon dioxide has ac- 
cumulated again. Breathing sufficiently forced to produce 
dizziness is not to be recommended. It is well to breathe 
deeply at a normal rate, however, and to keep the chest 
expanded. Deep breathing increases the capacity and vigor 
of the lungs and by keeping the chest well expanded the 
figure is improved, the heart and great blood vessels are 
given sufficient room and the diaphragm is allowed a free- 
dom of action which is highly beneficial to the internal 
organs. 

Bathing 1 . — The first function of bathing is to keep the 
skin and body clean. Otherwise the skin glands will leave 
upon the surface solid substances which are odorous and pu- 
trescible. Cleanliness not only keeps the skin healthy and 



66 HYGIENE: DENTAL AND GENERAL 

vigorous ; it avoids the presence of dirt which is a possible car- 
rier of disease ; and it is directly related to the self-respect 
of the individual. 

Perhaps something should be said of the temperature at 
which baths are taken. The hot bath opens the pores of the 
skin by stimulating the activity of the skin glands. It fol- 
lows that its too frequent use may make the skin dry by re- 
moving the oil and that such a bath leaves the individual 
highly susceptible to exposure to cold. It should not be 
taken too often or before going out into the open air. On 
the other hand, a hot bath or foot bath before going to bed 
helps to break a cold by bringing the blood to the skin and 
stimulating the circulation. 

If taken under proper conditions the cold bath is fol- 
lowed by a warm glow as the heat-regulating mechanism 
sends the blood back to the skin to neutralize the effect of 
cold. Such baths should not be prolonged over a minute 
and should be taken in a warm room when the skin is warm 
and followed by a good rub. They should not be taken 
within one hour after eating. Some find that cold baths 
use too much of their energy. By disturbing the circula- 
tion of the internal organs they may rarely result in con- 
stipation when taken regularly each morning. 

The indifferent bath in which the water is from 80 to 90 de- 
grees F. lacks both depressing and stimulating effects and 
is a good type of daily bath for many people particularly 
those who are not the most robust. 

Clothing/ — If the daily activities are to be performed 
with comfort suitable clothing is necessary. The great essen- 
tial in securing proper clothing is to provide constant ven- 
tilation for the body, that is, a continual change of the 
"aerial blanket." The type of clothing depends upon the 
nature of the fiber from which the clothing is made. The 
mesh of the round woolen fiber makes a cloth in which there 
are innumerable spaces filled with air and therefore the 
clothing is warm and not a good conductor of heat or cold. 



HYGIENE OF ACTION 67 

On the other hand, cotton fabrics are made from flat fibers 
readily pressed together in such a way that air is excluded 
from the meshes. The cotton cloth therefore, allows a ready 
exchange of air about the body and is a good conductor of 
heat. Rubber fabrics are not porous at all and allow no 
passage of air from one side to another. 

Woolen clothing is much warmer than cotton and is suit- 
able for the person who is doing out-of-door work or riding 
in the open during winter weather. It is an undesirable fab- 
ric for underclothing for people who are working indoors 
in the city. Our offices and shops are more likely to be too 
warm than too cold and the perspiration of the body in 
such a temperature is not readily evaporated through 
woolen. It is absorbed by a thick woolen garment and the 
body does not secure the relief it should have. At the end of 
four or five hours in the office, however, the garment is sat- 
urated with perspiration and all of the spaces formerly 
filled with air have become filled with water so that the 
underclothing is now a very good conductor of heat and 
when the person emerges into the cold air the water in the 
garment cools and the person is chilled in his cold damp 
clothes. For the man in town, therefore, it is much better 
to wear light underclothing and compensate for this by 
putting on heavy outer garments when emerging into cold 
air. If he is careful to walk briskly and keep up his bodily 
activity while out of doors or waiting for a car he has another 
means of increasing his bodily heat by increasing the oxida- 
tion process in the tissues. 



CHAPTER IV 

THE HYGIENE OF THE CENTRAL NERVOUS SYSTEM 

The proper care and conservation of that exceedingly com- 
plex machine, the central nervous system, upon which depend 
the sensations of consciousness and the efficiency of our men- 
tal and physical activities, is highly important. 

Function. — Through physiology and anatomy we early 
learned of it as a telephone-like system of communication hav- 
ing the central station in the brain, from which orders are 
constantly being sent during our waking moments, and having 
substations in our reflex and sympathetic nervous systems 
which are capable of handling minor emergencies flashed in 
as impressions from those parts of the body connected with 
each substation. The higher centers are subject to a contin- 
ual bombardment of impulses and stimuli from the sense- 
organs. 

This is a system composed of living substance which de- 
mands rest between periods of great activity and like other 
living tissues it increases, through use, its facility in the work 
it has to do. But if it is overused or abused it becomes 
hypersensitive. Stimuli which ought not to go beyond the 
substations are flashed through to the head station and trifles 
interfere with important activities. The person is irritable 
and the system is unable to carry out its normal functions. 

Without taking time to review the structure or function of 
the system in detail we shall consider the hygiene of the 
nervous system first in health and later in disease. It is 
common experience that the nervous system becomes tired 
at the end of the day's work. We know that the activities 
of the normal life place demands upon it which must be com- 
pensated by periods of 'rest. Our interest here concerns the 
efficient functioning of the nervous system and the important 

68 



HYGIENE OF CENTRAL NERVOUS SYSTEM 69 

ways in which rest and efficiency are secured by the normal 
and healthy individual. 

Concentration. — Perhaps the most important character- 
istic of the efficient nervous system is the power of concen- 
tration upon the task at hand. This is expressed in another 
way as the power of inhibiting undesirable stimuli. It is 
equally valuable in work and in rest. In work the individual 
inhibits from the center of consciousness those thoughts which 
are not germane to the subject in hand and also those stimuli 
which arise from the surroundings, trying to make their way 
to the center of consciousness through the portals of sight, 
hearing, touch, and perhaps taste and smell. In the efficient 
mind such stimuli and the inconsequential thoughts which 
arise from their associated ideas are rigidly excluded from the 
conscious thought. 

Recreation has the reverse process and the individual se- 
verely forbids thoughts and worries of his work to crowd in 
upon the enjoyment of the pleasures which he has allowed 
himself. For those people who, like great executives, are 
obliged to shoulder heavy responsibilities and are weighed 
down with numerous cares, the power of complete relaxation 
may be a saving grace. The criticism which nas sometimes 
been placed upon Lincoln and other men of this type for brief 
periods of light-heartedness in the midst of great problems is 
entirely unjust and unreasonable. 

The power of concentration is so intimately linked with 
efficiency and personal success that one may well ask how it 
may be secured or improved. Perhaps the most valuable aid 
is good health for with it the body is freed from minor pains, 
irritations and morbid sensations which are constantly break- 
ing into the train of thought of the physically unfit, opening 
the way for other distracting influences. 

Fondness for one's work is another important factor, since 
the work itself is making a constant appeal to the mentality 
and the volition. That is why there is a unity between the 
things people like to do and the things they do well. The ar- 



70 HYGIENE: DENTAL AND GENERAL 

rangement of one's workshop or desk in such a way that but 
one thing at a time is before the worker is important, and 
often it is of material assistance to occupy the hands with a 
pencil in making notes or sketches or with models, apparatus 
or instruments in studying technique. A man will do well to 
study the lighting, furnishings and equipment of the work 
place to eliminate distracting stimuli such as might arise from 
the reflected light of a glossy page, uncomfortable chairs or 
confusion of material. 

Habit. — Habit is another important factor in the conserva- 
tion of the nervous system. The processes of eating and 
dressing are exceedingly difficult for the young child, but 
by the adult they can be accomplished while the mind is de- 
voted to a more pleasant plane of thought than the necessary 
mechanical operations which are being performed. In the 
same way many activities connected with the daily work may 
be relegated to the realm of habit and thus the energy of the 
nervous system may be spared. Energy-saving habits are 
highly desirable but there are some dangers here. It goes 
without saying that good and not bad, hygienic and not un- 
hygienic habits should be formed. 

But apart from this psychologists have pointed out a group 
of so-called indifferent habits like the continual use of par- 
ticular words and phrases, the lack of reasonable variety in 
dress and recreation. They have pointed out that old age is 
a fixity of the nervous system which such long-continued 
habits have limited to particular channels of thought and 
action. If this is true it is possible to postpone old age by 
occasionally breaking up these habits in a determined fashion 
and freeing the mind from those ruts. 

Sleep, — To the normal person sleep is the great refreshing 
agent for the nervous system. The nature of this invaluable 
process still awaits complete explanation. There are two 
other types of unconsciousness ; namely, intoxication by drugs, 
in which sensations are blocked from reaching the central 
nervous system, and fainting, where consciousness is lost be- 



HYGIENE OF CENTRAL NERVOUS SYSTEM 71 

cause of an insufficient blood supply in the brain. Perhaps 
sleep has an element of both these types of unconsciousness, 
involving an altered brain circulation and the accumulation 
of the poisonous waste of bodily activity. 

The unconsciousness of sound sleep carries with it the com- 
plete relaxation of the body. This is the time when the body 
tissues make good their losses and for these reasons no satis- 
factory substitute for sleep can be found. It is probably this 
complete relaxation and its accompanying reduction of oxi- 
dation which makes a person chilly upon falling asleep in his 
chair or upon the couch in a room which has previously 
seemed warm enough. 

No doubt other factors than nervous fatigue are important 
in determining the amount of sleep required, since it varies 
greatly in individuals and is markedly greater in the young 
than in the old. Perhaps the most important factor here is 
assimilation. Heavy eaters are characteristically heavy 
sleepers, whereas ' ' Fletcherites " testify that the great reduc- 
tion in the amount of food eaten and the completeness of its 
mastication has reduced the amount of sleep which they find 
necessary. 

From seven to eight hours sleep is surely enough for the 
normal and healthy adult person. Nor should one conclude 
because there is an indisposition to rise in the morning that 
he has had too little sleep, it may be laziness and not weari- 
ness. It has been found by experiments that during the first 
two hours sleep is the heaviest and after that the person is 
waked more easily. This does not necessarily mean that the 
later hours of sleep are not equally restful but merely in- 
dicates that the nervous threshold has been lowered by the rest 
already secured. 

The difficulties in going to sleep promptly and in sleeping 
soundly do not usually exist for the normal individual if he 
is physically tired. Wakefulness often seems* more serious 
than it really is because the person may hear the clock strike 
regularly but yet obtain several hours el' lighl and dozing 



72 hygiene: dental and general 

sleep. Apart from physical exercises which induce bodily 
fatigue and secure a healthful sleep it is sometimes possible 
to avoid sleeplessness by the eradication of disturbing factors. 
The bed should be comfortable, the room dark and quiet, and 
the ventilation adequate. The person who sleeps where there 
is continuous noise, may say that he can sleep soundly, but 
he is probably doing his nervous system an injustice neverthe- 
less because he is partly wakened several times during the 
night. The banishment of exciting or worrying thoughts and 
the concentration of the mind upon inconsequential and hum- 
drum things, with the conscious attempt to relax the muscles 
of the hands and limbs and to adopt a slow rhythm of breath- 
ing, may also aid in promptly falling to sleep. 

Dreams. — The subject of dreams suggests itself. We must 
leave their philosophy to the psychologist, limiting ourselves to 
a brief statement of their importance from the hygienic view- 
point. There are two types of dreams, the remote and the 
recent. The remote type deals with experiences widely sep- 
arated from the activities of the day, the other' type deals with 
the worries and problems of our waking hours. It is the 
latter and not the former which should be a warning to us 
that our nervous system is not in a rested and normal con- 
dition. 

Change of Work. — Another method of resting the nervous 
system is by a change of work which puts in play a wholly 
different set of nerve structures. The man who has worked 
over a machine all day and is thoroughly tired may rest his 
nervous system as well as refresh his muscular system by 
playing baseball or tennis, but one must be careful, in this 
connection, not to commit the fallacy of assuming that nervous 
excitement, when it involves the nervous structures already 
tired, is rest. The man who is tired from driving an auto- 
mobile may forget his weariness by watching a moving picture 
of hairbreadth escapes ; but he is not rested thereby and it is 
only the strong stimulation of the overtired nervous structures 
which causes him to forget his fatigue temporarily. It is 



HYGIENE OF CENTRAL NERVOUS SYSTEM 73 

probably unfortunate for the nervous system as well as for 
family life that the habit of quiet home reading has been 
abandoned for a variety of exciting social amusements. 

Sunday Observance. — Sunday observance is a most impor- 
tant safeguard for the nervous system. In some experiments 
carried out at the Harvard Medical School (reported by Mar- 
tin, Withington and Putnam, American Journal of Physiol- 
ogy, 1914, Vol. XXXIV) it was shown that the sensory thres- 
hold, as measured by the least electric shock which could be 
felt through two fingers of the same hand, was lowest on Mon- 
day and highest on Saturday. In other words, the irritability 
or sensitiveness of the nervous system was highest after the 
day of rest or change in activity and was gradually reduced 
throughout the week. Apparently there is a cumulative fa- 
tigue of the nervous system by the work of the day which is 
only offset by Sabbath rest. This may account physiologi- 
cally for the fact that one day in seven has been set apart by 
people of nearly all races and religions as a day of rest and 
worship. It is certain that the observance of Sunday as a day 
of quiet when, for a time at least, the thoughts may be fixed 
upon immortal truths and upon things entirely separate from 
the struggle of the week is much to be desired in the care of 
the nervous system. 

Neurasthenia. — We have considered the care of the nervous 
system under the normal conditions of life and may now 
turn our attention to a discussion of the abnormalities of the 
overworked nervous system. We have hinted at the cause of 
this condition in mentioning cumulative fatigue which in- 
creases during the six working days of the week. When the 
strain upon the nervous system becomes too great and out- 
distances the normal rate of repair this cumulative fatigue 
results in serious disturbances ending in neurasthenia. 

There are a variety of causes for neurasthenia. In a few 
cases there are hereditary defects and the individual is handi- 
capped from the beginning of life with a highly irritable, hair- 
trigger nervous mechanism which was his unfortunate legacy 



74 HYGIENE: DENTAL AND GENERAL 

from one or both of his parents. But in most cases ineffi- 
ciency, discontent and lack of the ordinary degree of courage, 
perseverance, and kindliness are subject to hygienic control 
in some degree. The causes which will next receive consider- 
ation include overwork, emotion, bodily defects, eye strain, 
poor environment and the like. 

Overwork. — By overworking the mind, we mean putting 
too great a tax upon its endurance and not a too strenuous 
endeavor to concentrate the mental facilities. It is a case of 
too long hours and not too vigorous mental work. There is 
a maxim for students in regulating their hours of work that 
"8 plus 2 equals 10 but 10 plus 2 equals 8" when measured 
by the effective work done. In other words, there is a time 
limit in taxing the nervous system. 

Emotions. — The discussion of emotion in previous chapters 
has already suggested that not work but worry is harmful. 
The effects of the emotion upon the central nervous system 
are varied and important. 

If we trace the initial difficulty of indigestion due to the 
emotions, we find that the food lies in the stomach into which 
no digestive juices have been poured until abnormal and harm- 
ful decomposition changes begin to take place. Then as the 
food is finally passed into the intestines there is further de- 
composition because the protein digestion has not proceeded 
to a suitable degree in the stomach, and the bacteria in the in- 
testines decompose food substances into soluble and harmful 
end products, which are absorbed from the walls and produce 
that mild poisoning known as autointoxication. These dele- 
terious compounds have a specially marked effect upon the 
central nervous system. Autointoxication may be produced 
by continued unfavorable emotions like worry, fear, grief and 
pity, and it is increased by overeating, especially the over- 
eating of nitrogenous foods. It is one of the important 
factors in deranging the nervous system. 

The emotions have other relations to the nervous system 
than those connected with digestion. As Cannon clearly 



HYGIENE OF CENTRAL NERVOUS SYSTEM 75 

i 

showed, the emotions were designed as an aid to activity, by 
increasing the amount of sugar in the blood, producing a 
marked secretion of adrenalin, bringing digestion to a halt 
and increasing the capacity of the skeletal muscles. It is 
normal and probably more beneficial to the individual when 
his strong emotions find an outlet in action for then the im- 
pulses are translated into muscular activity. The external 
bruises of the school boy who fights are perhaps not as serious 
as the internal injury to the nervous system if there is no 
outlet for his anger. Even when a person has remained in- 
active there is some energy resulting from emotion or excite- 
ment, for these stimuli, upon reaching the muscles produce 
balanced contractions which may be indicated by tenseness 
of the muscles and features. 

It would seem therefore that for the normal and especially 
for the sluggish individual a reasonable amount of emotional 
excitement may be harmless and even desirable. But in so 
far as environment may be regulated to eliminate constant 
and undesirable emotions this should be done and whenever 
possible our emotions should be given a physical outlet, es- 
pecially those noble emotions which are produced by beauti- 
ful music and other forms of art, by the glories of nature, and 
the eloquence of gifted speakers. These stimuli should be 
translated into practical beneficent action. 

Bodily Defects. — There are many bodily defects which in- 
jure the central nervous system to a large degree. We re- 
member that pain has the same effect upon many organs of 
the body as do rage, fear and anxiety, and it seems reasonable 
that many mild bodily ills, which are tolerated when they 
should be corrected, will create continuous and harmful sen- 
sations in the central nervous system. Decayed teeth, 
troubles of the feet, such as fallen arches, ill-fitting shoes, corns 
and blisters, the wearing of orthodontia appliances by children, 
nasal obstruction with tonsillar and adenoid trouble, hem- 
orrhoids, and uterine displacement are examples of conditions 
which should receive prompl attention no1 only for their own 



76 hygiene: dental and general 

sake but for the injury which they do the nervous system. 

Eye strain is another important example. The nearsighted 
individual who is trying in vain to focus the eye, which is too 
deep, in such a way that normal vision shall be effected ; the 
farsight ed individual, who must put an extra strain upon the 
eye to focus it for near objects ; and the individual with astig- 
matism, who is always straining the eyes in the attempt to 
secure a clear image, are all bound to feel the effects upon the 
nervous system. On the other hand the correction of these 
difficulties often makes a new man or woman so far as temper- 
ament and congeniality are concerned. Perhaps it is the duty 
of the family to insist that such conditions are corrected for, 
since they have to live with the afflicted, they may have some 
rights in the matter. 

Stimulants. — Stimulants also should be considered in their 
effect upon the nervous system. Physiologists now agree that 
alcohol is not a stimulant but a narcotic. The reason for the 
feeling of exhiliration which follows a mild dose of alcohol is 
due to the paralyzing of the higher centers which have to do 
with inhibition. "When these centers are shut out from the 
rest of the nervous system the individual no longer feels the 
restraint of dignity and propriety. He gives free rein to his 
impulses and believes himself to be the soul of wit and the 
prince of goodfellows even when his activities are most 
asinine. As Professor Stiles has suggested, alcholic stimula- 
tion is like taking the brakes off on a train which is traveling 
down hill. It is easy to reach the lower level but it is hard 
to regain the heights. 

In a study of the intellectual capacity of a group of stu- 
dents before and after using alcohol the subjects were given 
certain simple mathematical problems which were accom- 
plished in a given time and the amount of errors checked. 
Later in the day after having partaken of small quantities of 
alcohol, the students were given similar problems to do and 
upon emerging from the room all testified that they had done 
the work more quickly and rapidly than in the first instance. 



HYGIENE OF CENTRAL NERVOUS SYSTEM 77 

The actual results were different from their expectations, 
however. They had taken longer to do the work and had been 
less accurate. The temporary banishment of care and the 
sense of obligation for the moment is a pleasure and may 
make the individual a more gracious social being but the re- 
sumption of responsibilities after the taking of alcohol is not 
so easy, and good health rather than this alternative should 
be the basis of our social graces. 

Many of the patent medicines have been shown to have an 
alcoholic content greater than champagne as the following 
table shows: 

ALCOHOL COMPABISONS 

Beer 4y 2 % 

Ale 8% 

Champagne 10% 

Swamp Boot 9% 

S. S. S 15% 

Varnesis 15% 

P'inkham's Vegetable Compound 15% 

Warner 's Safe Bemedy 15% % 

Tanlae 16% 

Pepto-Mangan 16% 

Hood's Sarsaparilla 16%% 

Vinol 18% 

Manola 18% 

Wincarnis 19% 

Paine 's Celery Compound 19%o% 

Peruna '. 20% 

Wine of Cardui 20% 

Plant Juice 20% 

Hostetter 's Bitters 25% 

It may not be inappropriate therefore to classify such sub- 
stance as stimulants especially since in many cases their real 
medicinal value is seriously in question. The man who is 
foolish enough to prescribe such a remedy for himself instead 
of seeking the advise of a good physician for his ills, ought 
to know what it really is which makes him "feel better" when 
he drugs the system with a patent medicine cocktail. 

Tea, coffee, and cocoa are not narcotic but are true stimu- 



78 HYGIENE : DENTAL AND GENERAL 

lants and their effect on the body is to increase activity. For 
most people their nse in reasonable quantities is not harmful. 
There are people, however, who find that one or the other of 
these drinks is a definite injury. To be of greatest value 
they should not be used regularly but only when some un- 
usual demand is to be placed upon the nervous system. 

The Neurasthenic. — We should consider what is meant 
by the functional disorder neurasthenia or as it is called in 
some of its milder stages, nervous fatigue or nervous prostra- 
tion. This is a type of disease which shows no lesions upon 
postmortem examination. It is functional rather than struc- 
tural. As the state of nervous impairment progresses the in- 
dividual indicates his condition by his demonstrativeness. He 
appears to be in a mild state of intoxication and indeed the 
accumulation of fatigue products in the brain may act in 
somewhat the same fashion as an alcoholic stimulant and may 
manifest itself in bodily movements and muscular contrac- 
tions. 

The neurasthenic is dissatisfied with everything around him 
because he is in an extremely sensitive condition. The room 
is too hot or too cold, there is too much light or too much 
noise. Impulses are sent to all parts of the body upon the 
slightest provocation. The skin is readily flushed or takes 
on the goose-flesh appearance, the heart is irregular, the di- 
gestion faulty, and the urine widely variable in composition. 
And perhaps worse than all is the subjective state, which is 
one of self-pity and disregard for the feelings of others, a 
condition separated from insanity only by the fact that all 
the worries have some foundation- — though often slight — in 
fact, and are not wholly imaginary. The neurasthenic is 
often not responsible for his condition. It may have been 
brought on by circumstances over which he had no control. 
Nevertheless, it is extremely difficult to treat him with un- 
mitigated kindness. It must be remembered that the troubles 
of which the neurasthenic complains are real to him and he 



HYGIENE OF CENTRAL NERVOUS SYSTEM 7 ( J 

must be treated with the consideration, tolerance and tem- 
perance which this broad perspective would suggest. 

Treatment.- — In describing the cause of neurasthenia as 
nervous fatigue the remedy has naturally suggested itself as 
suitable rest for the nervous system. Bodily defects must be 
first corrected and then physical exercise, which will concen- 
trate the mind upon other things than the worries of the in- 
valid, and sufficient sleep are important factors. Nervous 
fatigue yields more readily to these corrective measures in its 
incipient than in its latter stages. 

The dentist may frequently be of aid to the neurasthenic 
by encouraging him in a program of physical upbuilding and 
by assuring him that better teeth and the correction of other 
bodily defects will improve his health and relieve his nervous- 
ness. Such a patient in the dentist's chair should be treated 
with kindness, sympathy, and encouragement but with some 
degree of firmness. 



CHAPTEE V 

THE HYGIENE OF REPRODUCTION 

The Problem Defined. — The problem of reproduction in 
its broadest sense involves the replacing of one generation by 
another in the best possible manner. This inclndes compli- 
ance with the laws of heredity, a knowledge of the effects 
which the conduct of life may have upon the offspring, the 
best possible supervision over the hygiene of pregnancy and 
the early days of infant life, and the proper regulation of 
the sex life. 

HEREDITY 

Our knowledge of heredity has expanded rapidly during 
the past few years. We have here, however, only sufficient 
space to mention some of those facts which are important in 
guarding against the perpetuation of undesirable traits and 
physical conditions in offspring. The development of the 
subject has come from two lines of study, researches upon 
human heredity (eugenics) begun by Galton and researches 
in plant and animal breeding (genetics) begun by Mendel. 

Mendelian Inheritance. — Mendel's law enunciates the 
principle that opposing characteristics in the male and female 
parents do not blend in the offspring but the heredity units 
or genes remain distinct in the germ cells of the offspring 
recombining in future generations according to the law of 
probability and chance. 

To illustrate by an example from Mendel's work: when a 
pea plant which produces peas having a green color is crossed 
with one producing peas of yellow color all the peas produced 
in the first generation are of a yellow color but if plants of this 
first hybrid generation are crossed among themselves the peas 
produced in the second generation are in a definite ratio of 
three yellows to one green. 

80 



HYGIENE OF REPRODUCTION 81 

This law may be illustrated also from animal heredity. 
Among guinea pigs the crossing of a black strain with a white 
strain produces in the first generation only black offspring 
but if these pigs are bred among themselves the resulting off- 
spring are in the ratio of three black pigs to one white one. 

These results are most clearly understood in terms of the 
presence and absence theory which assumes that the yellow 
pea and the black guinea pig possess factors in the germ cell 
for yellow and black color, respectively, and that these color 




Fig. 15. — Inheritance in guinea pigs showing where the color (black) dominates 
over another color (white). (Kelicott.) 

factors are lacking in the green pea and the white pig. Such 
a characteristic appears whenever it is present in one or both 
of the germ cells united to create the new individual. We 
have here an explanation of the fact that offspring of the 
first generation all show a particular characteristic which has 
been inherited from one of the parents. We call such a char- 
acteristic as blackness in the guinea pig a dominant character- 
istic and the white color a recessive characteristic. The fol- 
lowing diagram illustrating the inheritance in guinea pigs 
shows why the first generation is completely black. All of 
the ova produced by the female guinea pig contain the char- 
acteristic for blackness and although they are united with 
sperms which lack this characteristic for blackness they still 



82 hygiene: dental and general 

carry the characteristic to the fertilized egg which is the be- 
ginning of the existence for the new individual. 

It may help us to understand the law better if we consider 
the explanation afforded by the general belief that the chromo- 
somes are bearers of the hereditary characteristics. The 
reader will recall from elementary studies of biology that the 
chromatin or deeply staining substance of the cell nucleus 
arranges itself into short threads called chromosomes when- 
ever there is a cell division. The number of these chromo- 
somes is constant for any species of animal. The number in 
all of the body cells is twice that in the mature sex cell. In 
other words, the final maturation processes of sex-cell develop- 
ment allow a separation of the chromosomes into two sets or 
groups so that there may be two kinds of sperms and two 
kinds of ova so far as the inheritance or non-inheritance of 
any characteristic is concerned. 

Returning to our example of the inheritance of color in 
guinea pigs we assume that the black color is produced by a 
special factor for pigmentation which is present in the sex 
cells of the black pig and absent in those of the white pig. 
It would appear that this factor is present in a chromosome 
inherited from the female parent but absent in the corres- 
ponding chromosome inherited from the male parent. It 
would therefore be present in all of the body cells of the hy- 
brid but when this pair of chromosomes again become sep- 
arated in the production of sex cells they would produce 
cells of different types. Therefore, we may have from this 
generation of hybrids, ova containing a factor for pigmen- 
tation and ova lacking the factor for pigmentation. Like- 
wise, we may have spermatozoa with this factor and others 
without it. so that there are four possibilities in the mating 
of cells within the uterus which must be in reality a matter 
of chance. The female cell with the character for blackness 
may unite with the male cell also having that characteristic 
and in that case the offspring produced receives the same in- 
heritance from both parents so far as this characteristic is 



HYGIENE OF REPRODUCTION 



83 



concerned, and therefore it is a "pure black" which will 
always produce black offspring. There is an exactly opposite 
possibility, namely, a union of two cells neither of which has 




Fig. 16. — Diagram illustrating the mechanism by which the unit factor, color, 
is inherited in guinea pigs. Animal A is a black female of pure stock. Such an 
animal is called homozygous and all of its sex cells are alike in carrying the 
unit character in question. Animal B is a homozygous white male; none of the sex 
cells have the characteristic for blackness. Animals C (female) and D (male) 
are hybrids. In each case half of the sex cells carry the characteristic for 
blackness and half of them lack this characteristic. When C and D are crossed 
the offspring of the second generation are in the ratio to three black to one 
white. The diagram illustrates each possible chance-combination of sperm and 
egg and it will be seen that, of the second generation animals, E is homozygous, 
F and G are heterozygous like C and D, and H is a homozygous white. 



the characteristic for blackness. Such a union results in a 
white pig of pure stock so far as color is concerned. 

Two other possibilities involve the mating of a female cell 
containing the characteristic with a male cell lacking the char- 



84 HYGIENE: DENTAL AND GENERAL 

acteristic or the exactly opposite condition. In either case 
we have a hybrid individual like the parents, that is, one and 
only one of the pair of chromosomes with which the color 




Fig. 17. — Eminent Twins. Edwin P. Grosvenor (left), prominent New York- 
lawyer, and his twin brother Gilbert Grosvenor (right), President of the National 
Geographic Society. (Photograph from Gilbert Grosvenor.) 

factor is connected contains the characteristic. Such animals 
are black in color because a pigment factor is present, al- 
though only in half quantity, and if again bred among them- 



HYGIENE OF REPRODUCTION 85 

selves we once more have a 3-1 ratio, that is, three black off- 
spring to one white. Naturally since this ratio depends upon 
probability or chance it is not exact. However, the greater 
the number of offspring the more exact is the ratio. This 
three to one ratio is in reality a ratio of one pure black: 2 
hybrid blacks : 1 pure white. Such an hereditary trait as the 
one just described is called a unit character. 

The study of genetics has taught us that many character- 
istics are inherited like the unit factors mentioned above. 
That being the case, it is obvious that these characteristics 
can be mingled by crossing different types and can be recom- 
bined in new combinations. For example, it might be pos- 
sible to cross a round red tomato with a yellow pear-shaped 
tomato and by continued breeding and careful selection secure 
a pure strain of red pear-shaped tomatoes. This indeed is the 
principle and the explanation of the wonderful work accom- 
plished by Luther Burbank in plant breeding. 

We can but marvel at the miracle of nature displayed in 
heredity. From each mating of sex cells, all of which look 
exactly alike when viewed with the highest power of the micro- 
scope, nature produces an individual different in character- 
istics from any other of the millions of people who inhabit the 
globe. It is difficult to explain how so many characteristics 
can be arranged spacially in the tiny germ cell unless we can 
conceive that these characteristics are caused by the infinite 
varieties in molecular pattern which are possible in the highly 
complex chromatin substances.* 

The mechanism of inheritance is in no way better illustrated 
than in the complete similarity of identical twins which re- 
sult from the separation of the embryo in its two-celled stage. 
Such twins must therefore receive identical hereditary fac- 
tors. Compare the records of the Grosvenor twins. As stu- 
dents at Amherst College they divided highest honors in 



*Miescher has shown that a molecule of albumen with forty carbon atoms may 
have as many as one billion stereoisomers, in protoplasm there are many kinds of 
albumen and other proteins, some with probably more than 700 carbon atoms. — 
Conklin. 



»b HYGIENE : DENTAL AND GENERAL 

the classroom and on the tennis field. Both have since 
achieved distinction, one as builder and director of the Na- 
tional Geographic Society, and the other as Assistant Attor- 
ney-General and partner in one of the most important law 
firms in America. They have never varied more than a pound 
in weight. In college their grades never varied more than one- 
tenth of one per cent. Although absolutely dependent upon 
glasses, each can wear the other's. Most of their tastes are 
similar. 

Haw Sex in the Offspring Is Determined. — There has al- 
ways been considerable speculation as to how sex in offspring 
is determined, because the question is of vital interest to par- 
ents who have a preference for either a son or a daughter; 
and it is interesting to find that the explanation offered by 
Mendelian studies in heredity and the microscopic studies of 
cell structure, which have for the most part been developed 
by Morgan, Wilson, and other American investigators, indi- 
cate that sex in the 'offspring cannot be controlled. We said 
previously that the body cells of animals contain twice as 
many chromosomes as do the sex cells. We must modify this 
general statement by saying that in the male of certain spe- 
cies this is not true. In such animals, of which it seems that 
man is an example, there is a chromosome which students of 
heredity speak of as the sex chromosome. 

Investigators believe that among humans all body cells in 
the female contain 48 chromosomes. This is true of the sex 
cells up to the time of the maturation process when the reduc- 
tion takes place and the ripe ova are found to have 24 chromo- 
somes. Among males the body , cells appear to contain 47 
chromosomes and when the maturation process takes place 
the odd chromosome or sex chromosome as it is called goes to 
but half of the cells resulting from the last division. We 
therefore Lave two kinds of spermatozoa in man, one having 
23 chromosomes, the other having 23 chromosomes plus the 
sex chromosome or 24. When the 23 chromosome sperm 
unites with the egg Ave have the beginning of a new individual 
of 47 chromosomes or a male. When the 24 chromosome 



HYGIENE OF REPRODUCTION 



87 



sperm unites with the egg we have a new individual of 48 
chromosomes or a female. Femaleness, then, is produced by 
the presence of two sex determiners, that is, it is an added 
characteristic superimposed upon maleness. The determina- 
tion of sex is therefore a matter of chance. 

Sex-Linked Characters. — Apparently the causative fac- 
tors of certain other characteristics are located in the chromo- 
some which determines sex and such unit characters are called 
sex-linked. Remembering the nature of the sperm cells de- 

APPLICATiOM OF nE/1D£LW/1 PKVOPLLo TO HlWWl I/ltlERlCVkX 

TRitfisnission or Color. £urtwtL5s 



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DETECT TO H» GSArtaacna OftLY. 



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DETECT TO ALL HER SOB ArtD TO fJALT HER 
GRArtDQIILDRtTl. 
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Fig. 18. — Transmission of color blindness. 



scribed above, we see that a sex-linked character in a man 
might be transmitted to his daughter but not to his son, if it 
were a dominant character. If it were a recessive character 
it could not be transmitted to any of the children from the 
father provided the mother were normal in this respect. 
Recessive sex-linked characteristics when transmitted by the 
mother would be apparent only in the sons. 

Color-blindness gives an example of this kind of inheritance 



88 HYGIENE: DENTAL AND GENERAL 

and since it is a recessive characteristic a color blind man 
need have no fear of transmitting the defect to his children 
if he marries a woman with no taint of this defect. This 
defect, however, may be passed on through his daughters to 
his grandsons but not to his granddaughters. The color blind 
woman on the other hand if married to a normal man even 
though she inherited color-blindness from both her parents 
would not transmit the defect to her daughters. Her sons, 
however, would all be color blind. The fact that this charac- 
teristic is located in the sex chromosome explains why color- 
blindness is more common in men than in women. Being re- 
cessive it is not apparent in the female unless it is inherited 
from both parents, while in the male it is directly received 
from the mother since it is not counter-balanced by a normal 
inheritance from the father. 

Inherited Diseases and Abnormalities. — There are several 
unit characters which have already been discovered in human 
heredity. Some of these are diseases but fortunately for the 
race these diseases are usually recessive and their evil effects 
may be counteracted by intermarriage with a normal stock. 
It must be remembered in this connection that pure strains 
for many characteristics are almost never to be found where 
inter-racial marriages have taken place for several genera- 
tions. 

The following table shows some of the conditions in man 
which are inherited according to Mendelian principle : 

MENDELIAN INHEKITANOE IN MAN . 
(Teratological and Pathological Characters) 
Dominant Eecessive 

GENERAL SIZE: 

Achondroplasy (Dwarfs with short stout Normal 
limbs but with bodies and heads of 
normal size) 
Normal Size True dwarfs (With all 

parts of the body re- 
duced in proportion.) 



HYGIENE OF REPRODUCTION 



89 



BANDS AND FEET: 

Brachydactyly (short fingers and toes) 
Syndactyly (Webbed fingers and toes) 
Polydactyly (Supernumerary digits) 

SKIN: 

Keratosis (Thickening of Epidermis) 
Epidermolysis (Excessive formation of 

blisters) 
Hypotrichosis (Hairlessness associated 

with lack of teeth) 

KIDNEYS: 

Diabetes insipidus 
Diabetes mellitus 
Normal 

NERVOUS SYSTEM: 
Normal 



Normal 



Normal 



Normal 
Normal 

Huntington 's Chorea 
Muscular Atrophy 
EYES: 

Pigmentary Degeneration of Eetina 
Glaucoma (Internal pressure and swelling 

of eyeball) 
Coloboma (Open suture in iris) 
Displaced lens 

EARS: 
Normal 
Normal 



Normal 
Normal 

Normal 

Normal 
Normal 
Normal 



Normal 
Normal 

Alkaptonuria (Urine dark 
after oxidation) 

Multiple Sclerosis (Dif- 
fuse degeneration of 
nerve tissue) 

Friedrich's Disease (De- 
generation of upper 
part of spinal cord) 

Meniere 's Disease (Dizzi- 
ness and roaring in 
ears) 

Chorea (St. Vitus Dance) 

Thomsen's Disease (Lack 
of Muscular tone) 

Normal 

Normal 

Normal 

Normal 
Normal 
Normal 



Deaf -mutism 

Otosclerosis ( Thickened 
tympanus with hard- 
ness of hearing) 



90 HYGIENE: DENTAL AND GENERAL 

(Sex-Linked Characters) 

Recessive characters, appearing in male when simplex, in female 
only when duplex. 

Normal Gower's Muscular Atro- 

phy 

Normal Haemophilia (Slow clot- 

ting of blood) 

Normal Color Blindness (Dalton- 

ism; inability to dis- 
tinguish red from 
green) 

Normal Night Blindness (Inabil- 

ity to see by faint 
light) 

Normal Neuritis Optica (Progres- 

sive atrophy of optic 
nerve) 

It is believed by some investigators that many other char- 
acteristics relating to normal variations of the hair, eye, 
skin, countenance, temperament, intellect and nervous system 
are inherited in Mendelian fashion. It is difficult to secure 
evidence in human heredity and the way in which many of 
these characteristics are inherited is still in doubt. 

Mentality and Heredity. — The importance of good he- 
redity has long been realized in characteristics or combina- 
tions of characteristics where the Mendelian principle is not 
present or where it has been impossible to demonstrate it. A 
ease in point is the inheritance of mental equipment. Mental 
ability is without doubt inherited as there is a high correlation 
between the mentality of fathers and sons, and between the 
mentality of brothers. There is also a high correlation be- 
tween the mental abilities of husbands and wives since there 
is usually selective mating through which men choose wives 
like themselves in mentality. (In contradiction to a popular 
belief most people marry "likes" not opposites.) This helps 
to raise the father and son correlation. 

The inheritance of mentality is not like the inheritance of 
a dominant or recessive unit character. In mentality, phys- 



HYGIENE OF REPRODUCTION 91 

ical stature, size and some other characteristics the offspring 
of widely different parents seems to be intermediate between 
the two. It would seem that there is either a blending of 
characteristics or else the quality in question is produced by 
many or ''multiple" unit factors. In the latter case if the 
father possessed twenty factors for mental ability and the 
mother ten the offspring would receive about fifteen and 
would therefore be intermediate in condition thus giving the 
appearance of "blending inheritance." 

Of course the question of environment enters here since 
children of most brilliant parents would have the best sur- 
roundings. It is not possible to give a general answer to the 
question as to which is the more important, heredity or en- 
vironment. Color blindness is due to heredity ; voice, speech, 
manners and indeed business success may be due to environ- 
ment. There is good evidence of the importance of heredity, 
however, in the production of essential mental and physical 
traits like long life and good constitution. For example, Dr. 
F. A. Woods has shown that the correlation between father 
and son in attaining distinction is as high in America as in 
the old countries of Europe. Now if success were entirely a 
matter of environment or "equal chance" there would be a 
lower correlation in America where, as in a young country, 
the opportunities are much more nearly equal than in the old 
countries with established castes. The "little red school 
house" cannot "give every boy an equal chance to be presi- 
dent." All men may be "created free" but they are not all 
"created equal." 

Dr. Woods has shown that if the people in the Hall of Fame 
on the Hudson were stood in line with the first beneath the 
center of the dome in the capitol at Washington the line made 
by the thirty would not reach outside the room. If the people 
of distinction as recorded in standard biographical diction- 
aries were stood behind them the line would reach outside the 
capitol and be continued for a mile or so down Pennsylvania 
Ave. Tf their contemporaries (the remainder of the American 



92 HYGIENE: DENTAL AND GENERAL 

people) were stood in line behind them the line would stretch 
to Chicago, on to San Francisco and up to Alaska. Of the last 
group one in 500 would be closely related to a man of distinc- 
tion, of the middle group one in four would have a near rel- 
ative of distinction and of the first group the people would 
average one such near relative apiece. Apparently there are 
'•'good strains" of human stock. (For further evidence the 
reader is referred to the recent and delightful book on Applied 
Eugenics, by Poponoe and Johnson.) 

We have the story of the family of the illustrious Jonathan 
Edwards which shows innumerable examples of the highest 
intellectual and moral worth among its descendants. On the 
other hand we have the story of the Jukes family investigated 
by Dugdale and concerning which we find the following sta- 
tistics. In five generations of the descendants of a worthless 
fisherman there were 1200 persons, including 200 who married 
into the family; the history of 1040 of these people is partly 
known or well known. About 300 died in infancy, of those 
remaining 7 were murderers, 60 were habitual thieves, 130 
were convicted criminals, 140 were physically wrecked by 
their own diseases and wickedness, more than half of the 
women were prostitutes, and 310 were professional paupers 
living in almshouses a total of 2300 years, not one of these 
people had a common school education and only 20 learned 
a trade, 10 of whom learned it in a state prison.' Here of 
course it is not easy to separate heredity and environment. 

Perhaps a somewhat more striking example of the import- 
ance of heredity is to be found in the story of the "Kallikak" 
family which has been cited by Dr. Henry Goddard (The Kal- 
likak Family, a Study in Heredity and Feeble-mindedness) . 
Here is the story of a revolutionary soldier who took advan- 
tage of a feeble-minded girl. From this indulgence a feeble- 
minded son was born, from him there descended a long line 
of degenerates, similar to those we have just described among 
the Jukes family. After the war, Kallikak, who was of good 
English descent, married a Quaker girl of good ancestry 



HYGIENE OF REPRODUCTION 93 

and from this legitimate union a long line of descendants has 
been traced, all of whom held position in the upper walks of 
life and none of whom were criminals or ne'er-do-wells. 

Feeble-mindedness. — The normal individual must accept 
his responsibility for race betterment in deciding the question 
of marriage, but the problem involved in preventing the prop- 
agation of the mentally deficient is one which society must 
handle. These feeble-minded people are divided into three 
groups according to mentality. The idiot has a mental age no 
greater than that of a normal child of two years, among im- 
beciles the mental age remains at about that of the four year 
period, while the moron has a mental age not greater than that 
of a twelve year old child. 

None of the four measures, which have been proposed for 
controlling the propagation of defectives is fully satisfactory. 
These measures are (1) education, (2) legislation, (3) segre- 
gation, and (4) surgery. Education of the general public 
may make society more alert to this problem for it is certainly 
startling when we realize that America has about half a mil- 
lion insane, feeble-minded, epileptic, blind and deaf; 80,000 
prisoners, and 100,000 paupers, who are supported at a cost 
well over a hundred million dollars a year. Laws limiting the 
marriage of feeble-minded people have been enacted in many 
states. Segregation is an ideal procedure where it can be 
applied but it is hopeless to attempt to secure all the afflicted 
and to place them in segregation hospitals. Resorting to 
surgery, the simple operation of severing the vas deferens 
or the slightly more complicated operation of severing the 
Fallopian tube, has been practiced but there is a serious 
clanger from the misuse of this surgical measure and a prac- 
tical difficulty in determining where it shall be applied. 

Heredity and Conduct. — A somewhat different phase of the 
Hygiene of Reproduction concerns a question which is natu- 
rally and often asked, namely, what effect will one's habits, 
virtues, and vices have upon the offspring. The present 
theory regarding the inheritance of acquired characteristics 



94 HYGIENE: DENTAL AND GENERAL 

is indicated in the surgical experiment of Dr. W. E. Castle 
in which the ovaries from a small black guinea pig were trans- 
planted into an albino (pure white) guinea pig, which was 
later mated with another albino. The offspring produced 
were black. This experiment shows that the hereditary qual- 
ities lay in the germ cells and not the body as a whole. 

We know also that embryologically the sex cells are early 
separated from the rest of the body and that the ova them- 
selves are already formed in full number at the time of birth. 
Mutilation experiments, like cutting off the tails of mice for 
several generations, have failed to show any shortening effect 
in inherited character. 

One may say that, from the standpoint of the race, the germ 
cell is of greater importance than the individual. This in 
general is true, for a person is like the father merely because 
he is decended from the same line of similar germ cells. The 
children of soldiers mutilated in war will be normal in every 
respect so far as the influence of these mutilations is con- 
cerned. An injury to the germ cells is much more serious than 
an injury to the body tissues of the individual. 

The number of cells of the body which, through one's de- 
scendants, may outlive the span of his own life is determined 
by the number of his children. We cannot change the 
hereditary characteristics which are embodied in these cells, 
but we should remember that these cells are a living part of 
the body and that they are subject to some of the same in- 
fluences which injure other tissues. We would expect to find 
the greatest vitality in those cells which are in a normal and 
healthy body. 

Certain poisons, which are distributed through the circula- 
tion, can reach these cells and a poison which is capable of 
serious injury to the growing or adult organism may thus be 
expected to reach in its baleful influences to the unfertilized 
sex cell. Lead is such a poison. When it gradually accumu- 
lates in the sj^stem it not only injures the body of the parent 



HYGIENE OF REPRODUCTION 95 

but it injures the germ cells as well. When there is serious 
lead poisoning in either the father or the mother the number 
of still-born children is greatly increased and those who do 
live are often of inferior vitality. 

The poison from syphilis is a substance which has most 
harmful effects especially upon the nervous system of children. 
This disease, moreover, as we shall see later, may be inherited 
in the active and contagious form. Gonorrhea is not inherited 
but there is danger of infection of the child at birth and the 
deleterious effects upon the sex organs of the parent may be 
serious. The case against alcohol is not as clear for the evi- 
dence of physical or mental inferiority in the children of 
alcoholics is conflicting. Possibly none of these substances 
are true race poisons as the offspring which do survive do not 
appear to pass on the defects to the next generation. But cer- 
tainly a belief in the noninheritance of acquired character- 
istics is not an argument for intemperance and incontinence. 

One may ask, however, whether this does not end the paren- 
tal obligation to exercise proper control over the temper and 
the nervous system generally. The answer would be that 
faulty hygiene in these respects will injuriously affect the 
general vitality of the individual and, what is more impor- 
tant, the environment of the children. Furthermore if the in- 
dividual is a confirmed neurasthenic perhaps he ought to con- 
sider the inadvisibility of rearing children. 

PRENATAL CARE 

But it is not enough that a child should have a good in- 
heritance; if it is to be well born it must live under proper 
conditions during the fetal period and if it is to start life 
without physical handicaps it must be given special and 
proper care during its early infancy and childhood. The 
great need is that mothers should realize that childbirth is an 
exceedingly important affair which involves the future health 
of two individuals and that the expectant mother should 



96 HYGIENE: DENTAL AND GENERAL 

early realize her condition and seek the advice of the best 
physician available.* In many centers of population the 
health departments carry out a proper function in providing 
health centers where advice upon these subjects can be se- 
cured. The physician has no cause to object to this arrange- 
ment since the woman who is able to pay for the services of 
her own physician will prefer to do so, and certainly physi- 
cians are willing to let someone else take care of their charity 
cases or prepare such cases for delivery. 

We may enumerate some of the reasons why it is important 
for the prospective mother to consult her physician or one of 
the health centers when, by the absence of menstruation or 
other signs of pregnancy, she realizes her condition. She 
should know that the heavy tax upon the system and the ex- 
treme muscular energy required at childbirth make it in re- 
ality "an athletic event" and she must begin training for 
this, the most important event in her life. She should have 
a thorough physical examination to see whether there are any 
organic defects. This should include an examination of the 
heart, the urine, lungs, and blood. Many bodily defects, if 
discovered at this time, can be corrected before childbirth 
and perhaps the life of both mother and infant saved thereby. 

The teeth should be given careful examination because 
their decay during pregnancy is extremely rapid. For this 
decay two probable causes have been suggested; the use of 
calcium salts in building bone tissue for the infant and the 
probable increase in acidity in the mouth of the expectant 
mother. Kepair work should put the teeth in perfect con- 
dition early in pregnancy and they should be given daily at- 
tention. 

If it is the first pregnancy the physician who is to take care 
of the case will also measure the pelvis to see whether there is 
danger of obstruction to labor because of the small size or ab- 



*Literature on prenatal hygiene can be secured from any State Department 
of Health or from the U. S. Public Health Service. 



HYGIENE OF REPRODUCTION 97 

normal shape of the pelvic canal. He will also be on the 
watch for albuminuria and eclampsia, and will require the 
patient to submit a sample of urine at least once a month. 
The latter condition which in its later manifestations pro- 
duces convulsions and unconsciousness may be largely avoided, 
even among women bearing the first child, by early detection 
and proper hygiene. Patent medicines advertised to make 
childbirth safe, easy and painless are frauds, and cannot be 
substituted for the services of a physician. 

The woman should realize that a double burden is placed 
upon her vitality. She must eat for the child and excrete the 
waste products produced by the metabolism of its body. It 
is probably the presence of some of these waste products which 
causes morning sickness with other systemic disturbances. 
Following is a list of directions prepared by Dr. Austin 
Brandt, a prominent obstetrician of Boston, for the use of his 
patients. 

DIRECTIONS DURING PREGNANCY 

Be careful to bring or send a clean specimen of the urine every 
week. Have your name and address on the bottle. Even if feeling 
perfectly well, come to the office at least once a month. 

If possible, drink each day six glasses of water between meals — one 
the first thing in the morning — two during the forenoon; two during 
the afternoon; and one just before retiring. 

Be careful to have the bowels move regularly each day; and report 
any inability in this direction. 

Keep the skin healthy by frequent bathing. Use only the shower 
bath during the last three weeks. 

For exercise, walking is the best. "Walk from one to two miles each 
day. Avoid lawn -tennis, horseback riding, and fast or rough motoring. 

Bathe the nipples night and morning with the solution prescribed. 

Wear loose clothing, capable of being adjusted to the increasing size 
of the abdomen. There is no objection to loose fitting corsets. Do not 
wear circular garters. 

Report headache, vomiting (especially after the middle of pregnancy) ; 
any marked swelling of limbs or face ; any disturbance of vision ; any 
bleeding or escape of water; any pain with regular recurrences. 



98 HYGIENE: DENTAL AND GENERAL 

Standards for Maternity Care. — The responsibility of the 
community or the state in providing the proper facilities for 
suitable maternity care is set forth in the following list of 
requirements prepared by the Children's Bureau of the U. S. 
Department of Labor as part of a set of minimum standards 
for child welfare. 

MATERNITY 

1. Maternity or prenatal centers, sufficient to provide for all cases 
not receiving prenatal supervision from private physicians. The work 
of such a center should include: 

(a) Complete physical examination by physician as early in pregnancy 
as possible, including pelvic measurements, examination of heart, lungs, 
abdomen, and urine, and the taking of blood pressure; internal exami- 
nation before seventh month in primipara; examination of urine every 
four weeks during early months, at least every two weeks after six 
months, and more frequently if indicated; Wassermann test whenever 
possible, especially when indicated by symptoms. 

(b) Instruction in hygiene of maternity and supervision throughout 
pregnancy, through at least monthly visits to maternity centers until 
end of sixth month, and every two weeks thereafter. Literature to be 
given mother to acquaint her with the principles of infant hygiene. 

(c) Employment of sufficient number of public-health nurses to do 
home visiting and to give instruction to expectant mothers in hygiene of 
pregnancy and early infancy; to make visits and to care for patient in 
puerperium; and to see that every infant is referred to a children's 
health center. 

(d) Confinement at home by a physician or a properly trained and 
qualified attendant, or in a hospital. 

(e) Nursing service at home at the time of confinement and during 
the lying-in period, or hospital care. 

(f) Daily visits for five days, and at least two other visits during 
second week by physician or nurse from maternity center. 

(g) At least ten days' rest in bed after a normal delivery, with suffi- 
cient household service for four to six weeks to allow mother to recu- 
perate. 

(h) Examination by physician six weeks after delivery before dis- 
charging patient. 

(Where these centers have not yet been established, or where their 
immediate establishment is impracticable, as many as possible of these 
provisions here enumerated should be carried out by the community 
nurse, under the direction of the health officer or local physician.) 



HYGIENE OF REPRODUCTION 99 

2. Clinics, such as dental clinics and venereal clinics, for needed 
treatment during pregnancy. 

3. Maternity hospitals, or maternity wards in general hospitals, suffi- 
cient to provide care in all complicated cases and for all women wish- 
ing hospital care; free or part-payment obstetrical care to be provided 
in every necessitous ease at home or in a hospital. 

4. All midwives to be required by law to show adequate training, and 
to be licensed and supervised. 

5. Adequate income to allow the mother to remain in the home through 
the nursing period. 

6. Education of general public as to problems presented by maternal 
and infant mortality and their solution. 

Statistics show the importance of better maternity care. 
The United States ranks fourteenth in a list of sixteen leading 
countries in its rate of maternal mortality. To quote from a 
special report of the Children's Bureau: 

Out of the 16,000 women who die (annually at childbirth) about 
7,500 die from diseases which are now to a great extent preventable or 
curable. 

In 1913 childbirth caused more deaths among women 15 to 44 years 
old than any other disease except tuberculosis; it caused in the same 
year among the same age group between three and four times as many 
deaths as typhoid fever. 

During the 13 years from 1900 to 1913 the typhoid rate has been 
cut in half, the tuberculosis rate markedly reduced, the diphtheria rate 
reduced more than one-half. In other countries there has been a de- 
crease in the death rate from childbirth, but in the United States * 
the new figures now published by the Census Bureau for the 
year 1916 (16.3 per 100,000 population) indicated that since 1900 
no decrease in maternal deaths had yet taken place. And physicians 
remind us that the Avomen who die in childbirth are few beside those 
who suffer preventable illness or a lifelong impairment of health. 

The loss involved is immeasurable. It does not stop with the loss 
of vigor and efficiency in the mother. It extends, in general, to the 
well-being of her children; and in particular to the motherless infant 
who faces a peculiarly hazardous existence. For example, in two of 
the cities included by the Children's Bureau in its study of infant 
mortality, the mortality rate among babies whose mothers died dur- 
ing the year following birth is compared with the rate for all the 
babies in the city. In Waterhury the rate among the motherless babies 



100 HYGIENE: DENTAL AND GENERAL 

is three times the average for the city; in Baltimore, five times the 
average for the city. 

Our enemies are chiefly ignorance and poverty — from a community 
point of view perhaps mostly ignorance. 

INFANT CARE 

The birth and the early days of infant life should represent 
the important culmination of all these weeks of care and it 
goes without saying that the best obstetrical services should be 
secured and that the mother should be given an opportunity 
to rest after this ordeal. During the prenatal period and the 
early days of infancy the district or public health nurse is 
an invaluable asset to the community and her activities under 
a properly managed health department have always shown 
a saving of mother and infant lives. 

It is exceedingly important that the mother should learn 
from her physician, from the health center or from literature 
on infant hygiene, the essentials in caring for her baby. She 
should know that four bottle-fed babies die to one that is fed 
by its mother and that apart from the greater danger of 
disease in artificial feeding, there is surely greater strength 
and vitality among babies who are breast-fed. She should 
eat only foods which agree with her or otherwise the quality 
of her milk may change; and if possible she should avoid 
weaning the baby in the hottest weather when intestinal dis- 
eases among children are most common. The baby's clothing 
should not be too warm or too tight. It needs fresh air and 
rest and not continual movement by being tossed in the air. 
The house must be kept clean. The daily bath should be 
properly administered; during the first three months the 
water should be about body temperature. 

All these and many other things are highly important to 
the welfare of the infant and are mentioned here only to re- 
inforce the statement that the importance of childbirth de- 
mands that the mother should properly inform herself through 



HYGIENE OF REPRODUCTION 101 

the aid of her physician or the organized health department 
of her state or city. 

The following quotation from a pamphlet on Breast Feed- 
ing Her Baby in the "Keep Well Series" of pamphlets issued 
by the U. S. Public Health Service, is an example of the ex- 
cellent, concise and specific health literature available from 
government agencies. 

Of every 100 bottle-fed babies 25 die in the first year of life; of 
every 100 breast-fed babies only 6 die in the first year of life. 

Nearly every mother can nurse her baby during the first three or 
four months of its life, and if she can nurse it for ten months so much 
the better. 

There may be an abundant supply of milk after the first few weeks, 
even if there is but little at first; the act of nursing causes the milk 
to come into the breasts and increases the supply. It is very important 
that the baby nurse regularly. 

In case the baby is not getting enough milk, the quantity lacking 
should be made up by properly prepared, safe cow's milk. Let a 
physician decide this. There may be only a temporary shortage on 
the mother's part, and with suitable care the milk will probably in- 
ci ease so that the breast supply will eventually become sufficient. 

Peace of mind is necessary for the nursing mother; she should have 
no worries; she should not get overtired. She should eat freely of 
her customary diet. The total quantity of fluids taken by her in 24 
hours should not be less than 2 quarts; more in hot weather. Stuffing, 
however, is unnecessary and undesirable. 

Tuberculosis in the mother is practically the only disease that always 
forbids nursing. Paleness, nervousness, fatigue, pains in the back and 
chest, or the return of the monthly sickness are not sufficient reasons 
for weaning, but when these symptoms are present or pregnancy ensues 
a physician should be consulted at once. 

Shortly after birth, boiled water, without sugar, may be given to 
the baby at regular intervals until the mother's milk supply is estab- 
lished. The baby, however, should be put to the breast at stated 
times, as often as the mother's condition permits. 

It is always wise to make nursing as easy as possible for the mother 
and to give her opportunities for rest. Therefore, the sooner the baby 
is satisfied and gaining on three-hour or even four-hour intervals the 
better. 

Convenient hours Cor nursing the baby are :is follows: 

1, Seven nursings in 24 hours. — G a. m., 12 noon, 3 p. m., G p. m., 8 
or 10 p. m., and once during the night. 



102 HYGIENE: DENTAL AND GENERAL 

2. Six nursings in 24 hours. — 6 a. m., 9 a. m., 12 noon, 3 p. m., 6 
p. m., and at the mother's bedtime; or at 6 a. m., 10 a. m., 2 p. m., 6 
p. m., 10 p. m., and one during the night. 

3. Five nursings in 24 hours. — 6 a. m., 10 a. m., 2 p. m., 6 p. in., 10 
p. m., or later. 

The baby should be offered cooled boiled water between feedings, 
especially during hot weather. 

The length of time for a nursing 1 varies with the infant and with 
the breast. The average infant rarely nurses longer than fifteen min- 
utes. The important point is to satisfy the baby. If there is any 
doubt, let it nurse longer, but not more than twenty minutes. If it 
is not satisfied after twenty minutes, consult a physician. 

It is customary to nurse only with one breast at each feeding, and 
to use them alternately. If, however, the baby does not get enough 
from one breast, give it both. 

It is important to keep the nipples clean; they should be washed 
before each nursing. Caked breast, or cracked nipples, although they 
may be harmful to the mother, do not make the milk poisonous for 
the baby. In both instances consult a physician, for a breast abscess 
may result if the condition is not attended to. The baby should usually 
be completely weaned at the end of the first year. Up to this time 
breast milk should be given to the baby as long as it thrives. It is 
better, when possible, to continue nursing through the summer and 
tc wean in the fall, but if the year-has not been completed in the spring, 
it is better to wean in the summer than in the spring. 

Do not wean the baby suddenly; it should be done gradually by 
replacing one breast feeding at a time with a bottle feeding. Several 
weeks are required for weaning. 

It is dangerous to wean a young baby. It should not be done for 
the convenience of the mother and should never be done without the 
advice of a physician. 

When the mother's milk is diminishing it is advisable to make up 
the lack with properly modified cow's milk. This may be done either 
by following one or more breast feedings with enough modified milk 
to satisfy the baby or by giving one or more full bottle feedings in 
place of a like number of breast feedings. 

The flow of breast milk tends to diminish when the baby nurses 
less than five times in 24 hours. When the baby is being nursed once 
every four hours and is not satisfied it is better to replace a nursing 
with the bottle. If, however, shorter intervals and more feedings are 
being used, a bottle feeding may take the place of a nursing without 
so much danger of decreasing the supply of breast milk. Most babies 
need additional food after the seventh month. 



HYGIENE OF REPRODUCTION 103 

The Obligation of the Community to the Infant and the 
Preschool Child. — The statistics of 1916 show that more 
than 75,000 babies in the United States died before they had 
completed their first month of life. From the latest available 
statistics the average number of deaths under one year of age 
per thousand births in the United States is 94. But there is 
ample room for improvement as shown by comparing this 
figure with the following rates for other countries : New Zea- 
land, 48 ; Australia, 56 ; Norway, 68 ; Sweden, 70 ; Switzerland, 
78 ; The Netherlands, 85 ; Ireland, 88 ; Denmark, 95 ; England 
and Wales, 96 ; Scotland, 107. 

England showed us what it is possible to do by actually 
reducing the infant mortality rate to the lowest point in her 
history while the world war was being carried on. This was 
accomplished by providing for the compulsory notification of 
births within thirty-six hours, government aid for local ma- 
ternity and infant welfare work amounting to not more than 
50 per cent of the approved expenditure, publicity explaining 
the government plan with its details for antenatal, natal, and 
postnatal work, and a great increase in the number of health 
visitors. The number of these visitors was increased from 
600 in 1914 to 1,024 in 1917 and the Board recommends that 
there should be one to every 400 births. The number of 
welfare centers in England and Wales increased from 850 in 
1917 to 1278 in 1918. 

The duty of our own communities is set forth by the Chil- 
dren 's Bureau in the following set of standards for Child 
Welfare relating to infants and preschool children. 

1. Complete birth registration by adequate legislation' requiring re- 
porting within three days after birth. 

2. Prevention of infantile blindness by making and enforcing ade- 
quate laws for treatment of eyes of every infant at birth and super- 
vision of all positive cases. 

3. Sufficient number of children's health centers to give health in- 
struction under medical supervision for all infants and children not 
under the care of a private physician, and to give instruction in breast 
feeding and in care and feeding of children to mothers, at least once 



104 HYGIENE: DENTAL AND GENERAL 

a month throughout the first year, and at regular intervals throughout 
preschool age. This center to include a nutrition and dental clinic. 

4. Children's health center to provide or to cooperate with sufficient 
number of public-health nurses to make home visits to all infants and 
children of preschool age needing care — one public-health nurse for 
average general population of 2,000. Visits to the home are for the 
purpose of instructing the mother in — 

(a) Value of breast feeding. 

(b) Technic of nursing. 

(c) Techndc of bath, sleep, clothing, ventilation, and general care 
of the baby, with demonstrations. 

(d) Preparation and technic of artificial feeding. 

(e) Dietary essentials and selection of food for the infant and for 
older children. 

(f) Prevention of disease in children. 

5. Dental clinics; eye, ear, nose, and throat clinics; venereal and 
other clinics for the treatment of defects and disease. 

6. Children's hospitals, or beds in general hospitals, or provision 
for medical and nursing care at home, sufficient to care for all sick 
infants and young children. 

7. State licensing and supervision of child-caring institutions or 
homes in which infants or young children are cared for. 

8. General educational work in prevention of communicable disease 
and in hygiene and feeding of infants and young children. 



SEX HYGIENE 

A properly arranged sex life cannot be insured by preach- 
ing fear and the consequences of immorality, but certainly 
the proper basis for a normal sex life in the developing child 
is adequate knowledge. The old-style false modesty and inno- 
cence has been shown in many cases to be not only useless but 
dangerous and pernicious. 

Sex Education. — Instruction in sex hygiene may be di- 
vided into three parts. Beginning at the age of three years 
the child is likely to ask questions as to whence it came. It 
should be given a truthful answer to its questions but no more. 
Old stories about the stork are not to be used, but on the 
other hand, this is not the time and place to teach sex hygiene 
and prophylaxis. This inquisitiveness dies out to a large ex- 



HYGIENE OF REPRODUCTION 105 

tent at about the age of five. By this time the child should 
learn that questions concerning these subjects are to be 
brought to the parent. 

The second stage of instruction is just before the age of 
puberty — twelfth to fourteenth years. At this time the child 
should be given certain information about the changes which 
it is soon to undergo. The instruction should be brief, per- 
sonal, and individual. This is a task for the parent, doctor, 
or friend, but not for the public school. The story is brief 
and can be told in a few minutes. It should not fire the imagi- 
nation but should warn against abuse and explain how it is 
that continence is entirely compatible with health. Such in- 
struction cements the friendship of the child. 

The third stage of instruction is to be given to young men 
and women at the age of sixteen to eighteen years, and con- 
cerns chiefly information regarding the venereal peril. Such 
a book as The Three Gifts of Life by Nellie M. Smith (Dodd, 
Mead & Co., New York, 1918) presents the story of sex to 
girls in a splendid and interesting way and may well be used 
to precede such a talk. Here again high school biology is not 
the place for the subject to be taught. 

Fear alone is not a deterrent, but an actual knowledge of 
the dangers in the path and a true picture of the beauty of 
virtue, appealing to the boy's love for sister and mother with 
a consideration of the obligations to the future wife, will go 
far to pave the way for proper living. "We may deplore the 
double standard of morals, but in changing it, we must see 
that the boy accepts the standard of the girl and that we 
preach equal restraint, not equal liberty, for belief in the 
■chastity of women is a most important restraining influence 
in the boy and young man. It is hardly necessary to add that 
a vigorous physical life, helpful social surroundings and ab- 
stinence from alcohol are most important factors. 

The third stage of sex instruction has recently been made 
much easier by the activities of the Federal and State depart- 
ments of health which have established special bureaus for the 



106 HYGIENE: DENTAL AND GENERAL 

control of venereal diseases and have made available moving 
pictures and pamphlets for information on this subject. The 
motion pictures prepared and shown under the auspices of 
the government and preceded by a medical talk from an of- 
ficial of the health department are very helpful. The boy or 
girl between fifteen and nineteen however should be accom- 
panied to these pictures by the proper parent. It is certainly 
undesirable that these pictures should be shown for profit and 
without proper supervision and accompanying medical in- 
struction, for then the mind of the boy or girl is centered 
upon the suggestive elements and not upon the medical facts. 
Public sentiment shoud prevent the improper use of these 
films. 

Summary. — In The Child's Ten Commandments to Parents, 
written some time ago for the American Journal of Public 
Health, I have summarized many of the obligations mentioned 
above : 

The Child's Ten Commandments To Parents 

And a new voice said to the people, 

I am the generation yet unborn who by being well born and 
properly cared for shall lead the race out of the bondage of 
disease to a healthier, better, and happier life. 

Thou shalt have no temporal gods before me. 

Thou shalt not bow down thyself before false images of 
temporal pleasures or become bound by overwork or by in- 
temperance in thy food, thy drink, or thy habits, for thy God 
is a righteous God and visiteth these sins in the form of phys- 
ical weakness upon thy children. 

Thou shalt not take my name in vain or think lightly of 
me in thy younger days for thou must begin when a boy or 
girl to prepare for my coming, by building a strong body and 
keeping it free from harmful substances and the taint of 
disease. 

Remember the pre-natal days and keep them properly. 
Other days shalt thou do hard labor if need be, but these are 



HYGIENE OF REPRODUCTION 107 

the months that are mine, and thou shalt seek advice of thy 
physician and so conduct thy life and that of thy family that 
I may become strong and not afflicted in these days of my 
coming. 

Honor thy sons and thy daughters that our days may be 
long upon the earth ; when we are babes give us the food which 
nature intended us to have and see that such hygienic meas- 
ures prevail in thy house and in the community where thou 
livest that we shall not be menaced by disease. 

Thou shalt not kill our confidence in thee by telling us 
lies about ourselves, and when at an early age we begin to 
ask from whence we came, thou shalt answer the questions 
truthfully and volunteer no further information. 

Thou shalt not make it easy for us to commit sexual ex- 
cesses by neglecting to tell us at the time of puberty what 
changes are to come upon our physical beings, and at the time 
of early manhood or womanhood thou or thy trusted friend 
shall explain to us individually the nature of those diseases 
which may inflict suffering upon us and upon those we love, 
explaining also the rules of personal hygiene, which will en- 
able us to avoid all excesses that would make us in our gener- 
ation unfit for parenthood. 

Thou shalt not steal our peace of mind by failing to inform 
thyself and consult with us frankly upon problems involving 
the proper development of the body, the mind, or the social 
and religious conscience. 

Thou shalt not bear false witness to what thou wouldst 
have us believe by leading a life which is unhygienic, empty 
of serious thought or immoral. 

Thou shalt not covet ease for thyself or thy children there- 
by forgetting the duties of every person as a citizen and a 
neighbor. 



CHAPTER VI 

THE NEW SCIENCE OF DISEASE PREVENTION 

Communicable Diseases. — Thus far we have considered the 
normal functioning of the body in the endeavor to point the 
way toward the normal conduct of life and the avoidance of 
diseases which arise from some derangement of the body 
mechanism from within. There is another group of diseases, 
those which arise from without the body, and a study of death 
statistics shows that these two groups of diseases are of about 
equal importance as causes of death. We are now to turn 
our attention to diseases which are comparable to the troubles 
with a machine arising from the entrance of foreign bodies. 
By the recent and rapid development of preventive medicine, 
preventive sanitation, and preventive hygiene the number of 
deaths from this group of diseases is being rapidly reduced, 
and it is here that the greatest opportunity for prevention 
lies. In the body, as in the machine, it is possible to prevent 
these injuries arising from without while the results of wear 
and tear will eventually make themselves felt. 

Early Theories of Disease. — It is difficult to realize that our 
knowledge of the cause of communicable disease does not date 
back of our own Civil War and that many people now living 
can distinctly remember the days when germs were unknown. 
Previous to this time the world had entertained vague notions 
as to the nature of these maladies, including the early con- 
ceptions of primitive man, the doctrines of Hippocrates and 
later the doctrines of Sydenham. 

The tendency of primitive man to personify all natural 
phenomena led to the earliest conception of disease as the 
activity of individual demons and according to this demonic 

108 



NEW SCIENCE OF DISEASE PREVENTION 109 

theory pain, disease, and death were "held to be caused by 
special evil spirits. 

From Hippocrates (460-359 B.C.) came the theory of the. 
four humors which held the essential elements of the body 
to be phlegm, blood, yellow bile, and black bile and disease 
to result from the improper balance between these substances. 
Our vocabulary still bears testimony to this belief when we 
speak of people of a sanguine, phlegmatic, ' or melancholy 
temperament. And this is not surprising since the theories 
of Hippocrates and his follower Galen dominated medical 
thought until the 16th century. 

We cannot be detained with a discussion of the various ad- 
vances in thought between this period and the establishing 
of our present knowledge except to mention the work of 
Thomas Sydenham (1644-1689) who asserted that "a disease 
is nothing more than an effort of nature to restore the health 
of the patient by the elimination of the morbific matter." 
In his belief in a definite substance, the materies morbi, as 
the cause of the disease, the "English Hippocrates," as Syden- 
ham has been called, took a definite step in advance and fore- 
shadowed the scientific recognition of infective organisms in 
the classical researches of Pasteur. 

Foreshadowings of the Present Theory. — Certain other 
scientific developments preceded the work of Pasteur. Most 
important was the development of the compound microscope 
about 1835. This was a necessary prerequisite to the study 
of infectious disease, as well as to the development of cytoiog- 
ical and histological knowledge. In 1837 the Italian investi- 
gator, Bassi, discovered that a contagious disease of silk worms 
known as muscardine was caused by a parasitic fungus and 
only two years later (1839) Schoenlein showed another of 
these mold-like plants to be the cause of favus or honeycomb 
of the human scalp. Here then we received definite infor- 
mation of a parasitic plant as the cause of a human disease. 

Fermentation and Disease.— It was in 1838 that Cagniard 
de Latour, and Schwann in studying yeast showed that alco- 



110 HYGIENE: DENTAL AND GENERAL 

holic fermentation is caused by a living plant. Their theory 
that this plant was the real cause of the fermentation process 
was at first disputed and was only thoroughly and finally 
established by Louis Pasteur (in 1857-1863) who went still 
further and showed that the "diseases" of beer and wine 
(abnormal sour and bitter -tastes) were produced by micro- 
organisms other than ordinary yeast. These had invaded the 
liquid and interfered with the usual alcoholic fermentation 
by producing undesirable fermentations of their own. 

It could hardly fail to occur to any thoughtful person that if this 
were true for certain diseases of wine and beer, it might well be true 
also for certain diseases of animals for if we consider step by step the 
course of any familiar fermentation and then do the same for any 
familiar infectious disease, w T e shall discover between them a remark- 
able similarity. For this purpose we may take the fermentation of 
apple juice, or cider, and smallpox. The juice of apples is heremeti- 
cally sealed and kept from exposure to air by the apple skin. In the 
making of cider this skin is broken, the juice is pressed out and of 
course exposed to the air, to dust, to the press, to the sides of the 
vessel which received it, to the strainer through which it passes, etc. 
At first, and for some time the juice is sweet, insipid, unfermented, 
but after some time it is plain that a change is coming over it. This 
change is called the "working" or active fermentation of the apple 
juice, and a closer examination will show that it is accompanied by a 
slight rise of temperature or -"heating" (which is a familiar phe- 
nomenon in many fermentations), as w r ell as by obvious chemical 
changes resulting in the evolution of gas and the disappearance of sugar, 
in place of which alcohol makes its appearance, giving to the whole 
process the name of "alcoholic fermentation." The fermentation of 
any particular portion of apple juice, however, is not indefinitely pro- 
longed. On the contrary, after a comparatively short time, thel proc- 
ess comes to an end, the evolution of gases ceases, and rest supervenes. 
Since Pasteur's classical researches we know that what has really hap- 
pened has been first, the seeding of the apple juice by (wild) yeast; 
second, the slow growth of this during the quiescent period; third, its 
active growth and "working" during the time of obvious fermenta- 
tion; and fourth, its gradual cessation of activity during the final 
period. In the case of the infectious disease known as smallpox the 
history is usually as follows. A susceptible patient must first be ex- 
posed to the disease, perhaps by contact with a person already affected, 
perhaps with clothing, letters, food or other materials handled by such 



NEW SCIENCE OF DISEASE PREVENTION 



111 



a person. After such exposure there is for a time no marked change; 
but because the disease has been shown by repeated experience to be 
nevertheless gradually developing-, as judged by the result and certain 
obscure premonitory symptoms afterward recalled, physicians have unan- 
imously agreed to name this the period of incubation. Sooner or later, 
headache, malaise, and other troubles appear, the patient becomes se- 
riously ill, a physician is called in, a rise of temperature or fever is 
discovered, the eruption and other marks of smallpox appear, and tht 
patient is plainly affected by active disease accompanied by every in- 
dication of profound disturbance and chemical change. But at last, 
if death does not supervene, recovery ensues, and the patient gradually 
becomes free from the disease by which he was temporarily overcome. 
We may add that the barrel of apple juice can undergo the alcoholic 
fermentation once only, and that the smallpox patient likewise, as a 
rule, has the smallpox only once. If now we tabulate side by side and 
in order, the principal phenomena of an alcoholic fermentation such as 
that of apple juice, and those of an infectious disease such as smallpox, 
we shall discover a remarkable similarity between them. 



A FERMENTATION 
(Apple juice) 

1. Exposure of the juice to air, 

dust, etc. 

2. Eepose and then slow change. 

(Growth of the ferment.) 

3. Active fermentation or "work- 

ing." Evolution of gas bub- 
bles, change of sugar to al- 
cohol. Rise of temperature. 

4. Gradual cessation of fermenta- 

tion. 

5. No further liability to alcoholic 

fermentation. 



AN INFECTIOUS DISEASE 
(Smallpox) 

1. Exposure of the patient to in- 

fection. 

2. Incubation. (Slow and insid- 

ious progress of the disease.) 

3. Active disease. Eruption, dis- 

turbance of the usual func- 
tions. Rise of temperature 
or fever. 

4. Slow convalescence (or death). 

5. Immunity to smallpox. 



The striking analogy here shown suggests something more. It cer- 
tainly justifies the suspicion of relationship, and shows well the natural 
fitness of the term "zymotic" (fermentative) for that class of diseases 
in which an analogy so remarkable is manifest. — Sedgwick. 

Pasteur. — Just as Pasteur had finished his important 
studies upon the nature of fermentation in wine and beer, 
thereby opening for himself a broad and alluring field for 



112 HYGIENE: DENTAL AND GENERAL 

further research, he was urged by the French government to 
undertake the study of a disease of silkworms. This disease 
was not only causing an annual loss of 100,000,000 francs in 
France but it was spreading rapidly to other countries so that 
it threatened the existence of the silk industry in all parts of 
the world. Pasteur was at length persuaded to attempt a 
solution of this problem and during the year 1865-1868 he 
proved this disease (pebrine) to be caused by a particular 
germ which could be grown by itself in suitable liquid. He 
also devised a method by which the eggs could be hatched and 
the silkworms reared without becoming infected with this 
disease. 

He had now definitely established the fact that certain 
minute plants (bacteria) were capable of producing partic- 
ular fermentations or souring processes in beer and wine and 
that another similar organism was the cause of an infectious 
disease which had killed so many of the silkworms. These 
bacteria could be grown by themselves and separated from 
other organisms in a suitable liquid and would always produce 
their own particular type of fermentation or disease when 
put back in the proper place. The foundations for the science 
of bacteriology and the germ theory of disease were thus se- 
curely laid. 

Lister. — Development from this point was rapid. Sir 
Joseph Lister, reflecting upon the significance of these inves- 
tigations of Pasteur, concluded that many wound diseases 
were probably infectious and set to work by the use of anti- 
septic dressings, sprays, etc., to establish his thesis which 
paved the way for the modern practice of sanitary or aseptic 
surgery. 

Koch and the Development of Bacteriology. — Then came 
the startling work of Robert Koch in 1875-78 who firmly 
established the science of Bacteriology by his researches upon 
anthrax and other diseases and by the adaptation of solid cul- 
ture media, prepared from gelatin substances, on which bac- 
teria could be readily grown and isolated. In his work with 



NEW SCIENCE OF DISEASE PREVENTION 113 

anthrax or splenic fever, a disease then very common among 
cattle and sheep, and occasionally attacking human beings, 
he found, as others had already observed, that there were 
minute or microscopic rods in the blood of animals which had 
died from this disease. These minute plants he removed from 
the tissues and planted in the clear liquid which constituted 
the aqueous humor of the ox's eye. The organism grew in 
this liquid from which minute quantities were introduced in- 
to fresh aqueous humor several times in succession until only 
the remote descendants of the plants first used were left. 
When these were introduced into healthy animals thy pro- 
duced typical anthrax. In other words the chain of proof 
had been made complete. A particular germ had been found 
in animals having a particular disease, it had been isolated 
and grown by itself in pure cultures, it had been introduced 
into healthy animals where it produced disease and the death 
of the animal, after which it could be recovered from the 
tissues. These four steps are known as Koch's rules for iden- 
tifying the cause of a disease. 

The use of solid media in 1881 was followed by the dis- 
covery of the bacillus of tuberculosis in 1882, the' discovery 
of the cholera vibrio in 1883, the bacilli of diphtheria and 
tetanus (lock-jaw) in 1884 and so on. The long list of dis- 
eases for which the causes are now known is evidence of the 
rapid growth of this field. We find diseases caused by a va- 
riety of microorganisms which are different in their appear- 
ance, their mode of living, and their effect upon the body. 
The list of infective organisms includes the round, the rod- 
shaped, and the spiral type of bacteria, fungous or mold-like 
plants like that producing honeycomb of the scalp and also 
animal parasites like those producing malaria and amebic 
dysentery. 

PREVENTIVE MEDICINE 

Preventive medicine may be properly limited to those proc- 
esses by which the individual is so treated as to become im- 
mune to particular diseases, in other words, the treatment of 



114 HYGIENE: dental and general 

the individual to prevent disease. We must look to Pasteur 
as the founder of this new science. In beginning his studies 
on immunity Pasteur had before him the example of small- 
pox and vaccination which had been developed and success- 
fully applied without knowledge of the germ theory of 
disease. Let us briefly review this story. 

Smallpox and Vaccination. — As early as 1717 Lady Mary 
Wortley ^Montagu, the wife of the British ambassador at Con- 
stantinople wrote to friends at home of the Turkish custom 
of "inoculating" against this disease. In this inoculation 
some ' ' matter ' ' derived from the pustle of a smallpox patient 
was introduced under the skin of a healthy person. Such 
an individual by choosing inoculation at a time when in good 
physical health, had a mild attack of the disease and was im- 
mune thereafter. The general adoption throughout Europe 
of this strenuous method of securing immunity speaks for the 
horror in which the disease was held. Previous to that time 
smallpox was the great scourge and destroyer of mankind, 
hardly one person in a thousand escaped it and so common 
was it that nearly everyone took the disease while yet a child 
so that it was regarded as a children's disease. 

Then came the wonderful discovery of vaccine by Edward 
Jenner in 1796. Jenner had been impressed as a student at 
Sudbury by the remark of a patient, in the person of a dairy 
maid, who said, ' ' I can not take smallpox because I have had 
cowpox." Testing this belief in his classical experiments 
Jenner transferred the vaccine virus from the eruption upon 
the hand of Sarah Nelms, — a dairy maid who had contracted 
cowpox from her master's cow by infection through a scratch 
in the hand, — to the arm of James Phipps, a boy about eight 
years old. This successful vaccination was followed by ex- 
posures to see that it provided a complete immunity against 
the disease, smallpox. 

Vaccination experiments were made elsewhere and in Bos- 
ton, in 1802, nineteen boys were vaccinated with cowpox in an 
experiment by the Board of Health. Twelve of these boys 



NEW SCIENCE OF DISEASE PREVENTION 115 

were later inoculated with smallpox with negative results 
while two unvaccinated boys who were also inoculated with 
smallpox virus both took the disease. The conclusion of the 
Board of Health that ' ' cowpox is a complete security against 
smallpox" we now know to be justified. By vaccination this 
great scourge has been practically eliminated. ' Indeed, so 
rare has it become, that even sensible, though unthinking, 
people forget the horror of the disease and give ear to those 
who oppose vaccination in spite of the fact that vaccination 
is now under almost perfect control and is the only sure pre- 
vention for smallpox. 

The Immunity in Anthrax and Rabies. — But it remained 
for Pasteur to develop the principle of immunity and to apply 
it to other diseases. Applying the principle of germ disease 
to this phenomenon Pasteur reasoned that if the infectious 
disease is a struggle between a man and a microbe it is prob- 
able that in vaccination for smallpox the struggle is less severe 
for the patient, because the germs have been weakened or en- 
feebled through residence in the body of the cow. This sug- 
gested that disease germs might be weakened by heat, cold, di- 
lution, starvation, etc., and Pasteur actually produced en- 
feebled or ' ' attenuated ' ' cultures of anthrax and chicken chol- 
era by these means. 

The story of his dramatic public demonstration of the 
practicability of vaccinating animals against anthrax or sple- 
nic fever is one of the most interesting in the history of 
science. Here he showed that animals which had been vac- 
cinated with attenuated cultures of the bacillus were not sub- 
ject to the disease after inoculation with virulent germs while 
animals which had not previously received such a vaccination 
and had been inoculated with the same virulent germs met 
death at the hands of the disease. 

The experiments began on May 5, 1881, at four kilometers' distance 
from Melun, on a farm of the commune of Pouilly-lc-Fort, belonging 
to a veterinary doctor M. Eossignol, Secretary-General of the Society 
of Melun. At the desire of the Society of Agriculture, a goat had been 



116 HYGIENE: DENTAL AND GENERAL 

substituted for one of the twenty -five sheep of the first lot. On the 5th 
of May they inoculated, by means of the little syringe of Pravaz,— 
that which is used in all hypodermic injections, — twenty-four sheep, 
the goat and six cows, with five drops of an attenuated splenic virus. 

On May 31 very virulent inoculation was effected. Veterinary doc- 
tors, inquisitive people and agriculturists formed a crowd around this 
little flock. The thirty-one vaccinated subjects awaiting the terrible 
trial stood side by side with the twenty-five sheep and the four cows, 
which awaited also their first turn of virulent inoculation. Upon the 
proposal of a veterinary doctor, who disguised his scepticism under the 
expressed desire to render the trial more comparative, they inoculated 
alternately a vaccinated and a nonvaccinated animal. A meeting was 
then arranged by Pasteur and all other persons present for Thursday, 
June 2, thus allowing an interval of forty-eight hours after the viru- 
lent inoculation. 

More than two hundred persons met that day at Melun. The Prefect 
of Seine-et-Marne, M. Patinot, senators, general counsellors, journal- 
ists, a great number of doctors, of veterinary surgeons and farmers, 
those who believed and those who doubted came, impatient for the 
result. On their arrival at the farm of Pouilly-le-Fort, they could not 
repress a shout of admiration. Out of the twenty-five sheep which had 
not been vaccinated, twenty-one were dead; the goat, was also dead; 
two other sheep were dying, and the last, already smitten, was certain 
to die that very evening. The nonvaccinated cows all had voluminous 
swellings at the point of inoculation, behind the shoulder. The fever 
was intense, and they had no longer, strength to eat. The vaccinated 
sheep were in full health and gayety. The vaccinated cows showed no 
tumor; they had not even suffered an elevation of temperature, and 
they continued to eat quietly. — Radot* 

Later Pasteur evolved a preventive treatment for Rabies, a 
disease in which the causative germ was not known. In the 
' ' Pasteur treatment ' ' for rabies spinal cords which are known 
to contain the germs of the disease are removed from infected 
rabbits and the strength of the virus is reduced by extended 
periods of drying. Then as now, the treatment was begun 
by introducing into a patient, which had been bitten by a 
rabid dog, an emulsion made from cord which had been dry- 
ing for two weeks. On the following days the emulsion was 
made up from fresher and fresher spinal cord until that which 

* Louis Pasteur: His Life and Labors. By his son-in-law. From the French 
by Lady Claud Hamilton. New York, D. Appleton & Company, 1885. 



NEW SCIENCE OF DISEASE PREVENTION 117 

had been dried only two days was administered. If admin- 
istered first this would have produced rabies and death. The 
story of the first application of this treatment to a human sub- 
ject in the successful treatment which Pasteur gave to the Al- 
satian boy, Joseph Meister, is of absorbing interest. (See Life 
of Pasteur quoted above.) 

In the cases cited above the body became immune or able 
to combat successfully the virulent germs by first conquering 
the attenuated or weakened germs of each disease. We may 
defer for the chapter on Immunity the discussion of the 
weapons and methods of this struggle because the activities 
of the germs and the body are complex. 

Diphtheria and Antitoxin. — There is one disease, however, 
which is of special interest because a definite poison (toxin) 
is secreted by the germ just as the poison alcohol is secreted as 
a metabolic product of the yeast cell. In diphtheria a toxin 
is poured out from the bacterial cells which is extremely poi- 
sonous to certain cells in the body. 

In 1892 Berhing and Kitasato discovered that the blood of 
an animal which had been made immune to the toxin of diph- 
theria was able to neutralize or impair the virulence of such 
a toxin, while the serum of the nonimmune animal could not. 
They found the poison produced by the bacillus of diphtheria 
to be soluble and separated it from the germs which produce 
it. We now secure the antitoxin which has the power to neu- 
tralize this poison from the blood of horses which have been 
made immune b}^ injecting small and increasingly larger 
doses of toxin. Since this antitoxin may be secured by itself 
it may be used in treating the disease if introduced into the 
body of the patient, where it neutralizes the toxins produced 
by the diphtheria bacilli. 

PREVENTIVE SANITATION 

We have spoken of the new knowledge of germs as the cause 
of disease and the development of the principle of immunity, 
which forms the basis of preventive medicine. The second 



118 HYGIENE: DENTAL AND GENERAL 

great division of this new science of disease prevention is pre- 
ventive sanitation. 

The knowledge that diseases were produced by germs and 
that the spread of disease is due to the infection of the healthy 
individual with these living germs makes it clear that for self- 
protection society must prevent the voiding of germs by the 
diseased person where they will be picked up by other in- 
dividuals. The responsibility of society was recognized even 
before the development of the germ theory of disease was well 
established, for as early as 1874 there was a belief among 
experts that "the existence of specific poisons capable of pro- 
ducing cholera and typhoid fever is attested by evidence so 
abundant and strong as to be practically irresistible. These 
poisons are contained in the discharges from the bowels of 
persons suffering from the disease." (Rivers Pollution Com- 
mission of 1868, Sixth Report, London, 1874.) 

The Epidemic of the Broad Street Well.— One of the foun- 
dation stones for this belief was laid in the excellent work of 
Dr. John Snow of London in 1854, in investigating an epi- 
demic of Asiatic Cholera, which was traced to the water of 
the Broad Street well. Inasmuch as this was the beginning 
of the science of epidemiology we may briefly give it our at- 
tention. 

During the epidemic the death rate in St. James Parish 
was far higher than that for any other district. Moreover 
the deaths were unequally distributed and had nearly all 
taken place in the vicinity of Broad Street. It appeared there- 
fore, that there must be some other factor involved than the 
usually accredited causes of epidemics, such as meteorological 
conditions, the general impurity of the air, the nature of the 
soil and the density of the population. From the beginning of 
the outbreak Dr. Snow had taken the trouble to get the num- 
ber and location of all the fatal cases. He found that 83 
deaths took place during three days beginning with August 
31. To quote from his report: 



NEW SCIENCE OF DISEASE PREVENTION 



119 



On proceeding to the spot I found that nearly all the deaths had 
taken place within a short distance of the pump in Broad Street. There 
were only ten (10) deaths in houses situated directly nearer to another 
street pump. In five (5) of these cases the families of deceased per- 
sons told me they always sent to the pump in Broad Street, as they 
preferred the water to that of the pump which was nearer. In three 
other cases the deceased were children who went to school near the 




• • LOCATION OF PUMPS. 

• • LOCATION OF FATAL CHOLERA CASES 

BOUnOART OF EQUAL OISTAMCES BETWEEI 

BROAD STREET PUMP ANO ^"i^iS. 

OTHER PUMPS. 

(AFTER THE ORIGINAL MAP BY 

OR. jonn snow.) 



Fig. 19. — Cholera deaths in the epidemic of the Broad Street Well. 

pump in Broad Street. Two of them were known to have drunk the 
water, and the parents of the third think it probable that it did so. 
The other two deaths beyond the district which the pump supplies rep- 
resent only the amount of mortality from cholera that was occurring 
before the eruption took place. 

With regard to the 73 deaths occurring in the locality belonging, as 
it were, to the pump, there were 61 instances in which I was informed 



120 HYGIENE: DENTAL AND GENERAL 

that the deceased persons used to drink water from the pump in Broad 
Street, either constantly or occasionally. In six (6) instances I could 
get no information, owing to the death or the departure of every one 
connected with the deceased individuals; and in six (6) cases I was 
informed that the deceased persons did not drink the pump water be- 
fore their illness. 

The result of the inquiry consequently was that there had been no 
particular outbreak or increase of cholera in this part of London, ex- 
cept among the persons who were in the habit of drinking the water of 
the above-mentioned pump well. 

I had an interview with the Board of Guardians of St. James Parish 
on the evening of Thursday, 7th of September, and represented the 
above circumstances to them. In consequence of what I said the handle 
of the pump was removed on the following day. 

Among the unusual causes which added confirmation to this 
belief Dr. Snow describes two as follows : 

A gentleman in' delicate health was sent for from Brighton to see 
his brother at No. 6 Poland Street, who was attacked with cholera and 
died in twelve hours, on the first of September. The gentleman ar- 
rived after his brother's death and did not see the body. He only 
stayed about twenty minutes in the house, where he took a hasty and 
scanty luncheon of rump steak, taking with it a small tumbler of cold 
brandy-and-water, the water being from the Broad Street pump. He 
went to P'entonville and was attacked with cholera on the evening of 

the following day, September the 2nd, and died the next evening. * 
* * * 

The deaths of Mrs. E and her niece, who drank the water from 

Broad Street at the West End, Hampstead, deserve especially to be no- 
ticed. I was informed by Mrs. E — 's son that his mother had not been in 
the neighborhood of Broad Street for many months. A cart went from 
Broad Street to West End every day, and it was the custom to take 
out a large bottle of the water from the pump in Broad Street, as she 
preferred it. The water was taken out on Thursday, the 31st of 
August, and she drank of it in the evening and also on Friday. She 
was seized with cholera on the evening of the latter day, and died on 
Saturday. A niece who was on a visit to this lady also drank of the 
water; she returned to her residence, a high and healthy part of Isling- 
ton, was attacked with cholera, and died also. There was no cholera 
at this time, either at East End or in the neighborhood where the 
niece died. Besides these two persons only one servant partook of the 
water at West End, Hampstead, and she did not suffer, or, at least, 
not severely. She had diarrhea. 



NEW SCIENCE OF DISEASE PREVENTION 121 

The investigation was further continued by the Rev. H. 
Whitehead who studied the cause of the sudden pollution of 
the Broad Street well which he believed must have been the 
cause of the epidemic referred to above. He found that in 
house No. 40 Broad Street there had not only been four fatal 
cases of cholera at the time of the epidemic but there had 
been earlier cases of an obscure nature which were probably 
cholera, and that the dejecta from these had been thrown 
into a cesspool very near the well. Further investigation 
showed that the bottom of the main drain from this house 
lay 9 ft. 2 in. above the water level and that one drain was 
so broken down as to leak like a sieve. Moreover, the poorly 
constructed cesspool over which a common open privy had 
been placed connected with the drain. The walls of the cess- 
pool were in the same leaky condition and the removal of the 
soil showed that there had been a direct drainage from both 
cesspool and drain into the well. The water had apparently 
been long polluted but it required a specific infection to pro- 
duce the outbreak of Asiatic Cholera. 

Thus water-born disease was known to exist before it was 
known that the disease was produced by germs. In other 
words, at this time it was believed that filth produced certain 
diseases because it produced, harbored and developed certain 
poisons instead of furnishing, as we now know to be the case, 
a temporary abode for the germs which have been thrown off 
from the body of a previous case of the disease. 

We might describe other epidemics of intestinal disease 
which have been traced to polluted water before and after 
the discovery of the germs of these diseases. To this we could 
add the story of scores of epidemics of typhoid fever, scarlet 
fever, and diphtheria, which have been traced to milk and the 
description of various other methods of infection by means 
of food or some other intermediate substance. 

A Typhoid Fever Epidemic From Oysters. — Perhaps one of 
the most famous epidemiological investigations on record is 
that made by Professor H. W. Conn of Wesleyan University 



122 HYGIENE: DENTAL AND GENERAL 

in 1894. In this year there was an outbreak of typhoid fever 
about October 20 which included over twenty cases among 
the men of this coeducational college. No common bond was 
found among the victims of the disease. They boarded at dif- 
ferent tables and many lived in private houses in town. The 
wells of the college campus were excluded on the ground that 
they were used by town people as well as college students and 
no typhoid fever had occurred among the townspeople. 

Professor Conn's complete and careful studies developed 
along the lines indicated by the following facts. With three 
exceptions all the sick men belonged to three fraternities. 
There were no cases among the women of the college. The 
water, ice cream, butter and fruit eaten at these fraternity 
houses were all excluded as sources of the disease because they 
had been used by other people in the town and college. The 
study of the dates showed that infection took place about the 
time of a series of fraternity suppers. One of the cases not 
belonging to a fraternity had attended such a supper. The 
menu of these suppers were studied and all foods excluded 
except raw oysters. It was then found that the women of 
the college did not hold any special supper on this date and 
did not eat raw oysters. Of the other four fraternities, among 
which there were no cases, two did not use oysters at initiation 
suppers, one obtained them from Hartford instead of Middle- 
town dealers and the fourth used oysters but in the cooked and 
not the raw state. None of the families in town which bought 
oysters from this lot had eaten them raw. An attendant who 
had eaten oysters from this batch in the home of the dealer 
had had a mild run of the fever. Many alumni and five Yale 
students were present at the banquet. Among these there 
were several cases of slight illness, diarrhea, weakness, and 
four cases of genuine typhoid fever. Two of the five Yale 
students developed the disease. 

The study of the source of the oysters showed that they 
had been taken from deep water in Long Island Sound, had 
been brought to the mouth of a creek near Fair Haven, 



NEW SCIENCE OF DISEASE PREVENTION 123 

Connecticut for fattening. Three hundred feet from the beds 
where the oysters were fattened there existed the outlet from 
the sewer of a private house in which there were two cases of 
typhoid fever. The current of water at this point showed 
that the effluent from this sewer would almost certainly be 
distributed over the beds in which the oysters were fattened. 

These examples of the early and startling discoveries of the 
transmission of disease from the sick to the well by means of 
some intermediate substance show the basic principle upon 
which the science of preventive sanitation has been developed. 

The knowledge of germs as the cause of disease, their via- 
bility in water, milk, and other foods, and the methods by 
which they may be destroyed has made it possible to develop 
scientific means of sewage disposal, water purification, and the 
protection of food materials. The practical details of applied 
sanitation in these various fields will be later considered. 



PREVENTIVE HYGIENE 

Preventive hygiene or the conduct of individuals in such 
a way as to avoid infection and communicable disease is based 
upon our knowledge of both preventive medicine and pre- 
ventive sanitation. Our habits are now influenced by our 
knowledge of the germs of particular diseases, their mode of 
life and the manner in which they may be transferred; so 
that in our daily activities we avoid opportunities for infec- 
tion. Promiscuous kissing, the use of common drinking cups, 
and the eating of food prepared and served by people of un- 
cleanly habits whose freedom from infectious disease can not 
be vouched for; these and many other unhygienic habits are 
automatically condemned by our knowledge of germ diseases. 
These dangers of infection will be considered further in our 
discussion of special diseases. 

Resistance. — Preventive hygiene must consider still another 
feature in resisting infection and particularly in successfully 
withstanding an infectious disease. Pasteur demonstrated 



124 HYGIENE: DENTAL AND GENERAL 

that the outcome of the battle between man and the microbe 
may be determined by weakening or attenuating the latter or 
by building up a specific resistance of the human body. 
Dr. Theobold Smith has spoken of disease in terms of the 

formula D = ; when D ===== the disease ; N = the num- 

R 

ber of organisms in the initial infection ; V = the virulence 
of the germs ; and R ===== the resistance of the individual. 
This resistance in many cases is specific for the disease 
in question but for other diseases, like Tuberculosis, the re- 
sistance may be related to the bodily vigor and general health 
of the individual. So that personal hygiene, which assists in 
building up a strong and healthy body, is related to disease 
prevention and is important in disease as well as in health. 

Summary. — We have seen the origin of three united sciences 
by referring to the history of disease prevention and the dis- 
covery of germs as the cause of disease. 

Preventive medicine reaches back to the experiments of 
Pasteur in producing immunity to a specific disease and in- 
volves all the more recent developments of this art by the use 
of specific vaccines, antitoxins, viruses and drugs to assist the 
person to throw off or withstand infectious diseases. Prevent- 
ive sanitation rests upon this new knowledge of disease causa- 
tion and by its application prevents the spread of infection 
from the sick to the healthy either directly or indirectly 
through the application of quarantine, the supervision of 
water, milk, and other food supplies, the purification of sew T - 
age, and the prevention of other conditions w T hich would make 
it possible for live germs to reach and infect healthy individ- 
uals. Preventive hygiene recognizes the infectious agents of 
disease and prescribes for individuals a course of conduct 
which is best calculated to avoid infection. 



CHAPTER VII 

ESSENTIAL FACTS OF IMMUNITY 

The presence of an immunity is easier to understand than 
the process by which it is secured. For the ordinary in- 
dividual the fact is all important but the science of immu- 
nology is the foundation of the art of preventive medicine and 
a brief statement of the essential facts in this rapidly develop- 
ing science has a place in any extended discussion of the sub- 
ject of hygiene. 

Immunity Denned. — Immunity is a common property of 
life which may be denned as the power of the organism to re- 
sist infection. It is opposite in meaning to the word suscep- 
tibility and both these words are relative terms. Immunity 
may be complete, or so weak as to be hardly appreciable. In 
many instances we use the term resistance as equivalent to 
immunity. 

Another variable quantity, which is always related to the 
immunity of the patient, is the virulence of the disease-pro- 
ducing organism. By virulent we mean poisonous or deadly 
and we find that different strains of germs have varying abil- 
ities in their power of evil just as individuals have the 
varying powers of resistance. 

We may illustrate immunity with an analogy from inter- 
national experience. It is not now difficult for us to con- 
ceive of a nation thirsting for world power and opposed to 
the welfare of the great body of humanity outside that nation. 
The people of such a country may represent the germs of a 
disease and the great body of humanity, the person subject to 
the disease. The individuals of such a nation usually appear 
innocent enough and, like the germs of disease, quite similar 
to their harmless neighbors. There finally arises an oppor- 

125 



126 HYGIENE: DENTAL AND GENERAL 

tunity for the invasion of other lands and these people make 
war upon the rest of the world just as the germs enter into 
a struggle with the human body. If they are successful the 
life of the invaded nations comes to an end; if they are not 
successful in their war they are eliminated from the territory 
which they have overrun and their armies are reduced in 
strength and vitality, for the time being, just as the virulence 
of influenza seems to be reduced after the first severe epidemic. 
But the other peoples of the world, if they are wise enough 
to realize the danger from this lust for world conquest, will 
set up barriers against the return of a world war and if 
these barriers are strong enough future recurrences may be 
avoided. These barriers, like the factors of immunity, are 
varied, numerous and complex. They may consist of a new 
army to combat the destructive forces of the enemy, of mili- 
tary barriers set up against the entrance of the foe or a gen- 
eral readiness of the peoples to respond immediately to a 
threat of a new attack. Likewise the human body when at- 
tacked by the germs of disease may create new defensive sub- 
stances which remain in the blood, the tissues subject to mi- 
crobial invasion may become more resistant to the particular 
organism or the whole bodily reaction may be more prompt 
and effective at a second attack. 

Our knowledge of immunity has been gained from the ob- 
servation of diseases and from experimental biology but not 
from chemistry. In other words, we are not yet able to state 
the chemical reactions in immunity and disease and we must 
expand the science by a study of the reactions of experimental 
animals and the reactions of the immune substances which 
they produce. 

We should recognize at the outset that the resistance of an 
individual to disease is determined by two factors, his general 
bodily health or vigor and the presence or absence of specific 
immune substances in the blood. These two factors are not 
of the same relative importance in all diseases. In cases of 
tuberculosis, pneumonia and colds or in cases of sepsis, bodily 



ESSENTIAL FACTS OF IMMUNITY 127 

vigor is very important. In most of the contagious diseases 
such as scarlet fever, small pox, typhoid fever, and measles, 
however, general good health is of little importance in with- 
standing the infection and immunity can only be secured 
through the presence of immune substances in the body. It 
may be that the importance of bodily vigor in combating tu- 
berculosis, colds and other respiratory diseases, is related to 
the important part played by the living cells (phagocytes). 
Although the diseases in this group are not numerous they are 
very important and we may do w r ell to begin by enumerating 
some of the most important factors in destroying immunity 
through the reduction of bodily vigor. 



NONSPECIFIC IMMUNITY 

The things which most frequently break down the non- 
specific immunity or general vitality are the following: 

1. Fatigue. — Experimentally it has been found that white 
rats are more susceptible to anthrax after being worked in a 
revolving cage ; and it has also been found that the defensive 
powers of dogs, rabbits and guinea pigs against typhoid are 
reduced by excessive exercise. It is hard to explain how 
fatigue produces these results unless we accept the suggestion 
that katabolic products of muscular activity are injurious to 
the cells, especially the white blood cells which, as we shall see 
later, play an important part in immunity. It is known that 
these products are acid and that some of the protective sub- 
stances in the body (alexins and opsonins) act best in an al- 
kaline medium. 

2. Exposure to Wet and Cold.— Exposure to wet and cold 
reduces the power of resistance to disease, as has been demon- 
strated in the case of fowls which are naturally immune to 
anthrax but contract the disease after standing some time in 
cold water. We know that such exposure cools the blood and 
must therefore reduce the activity of the leukocytes. It may 
also reduce the production of defensive substances in the 



128 HYGIENE: DENTAL AND GENERAL 

body. This relation to temperature would explain how mus- 
cular exercise reduces the danger of diseases under exposure 
to cold and wet by keeping up the body temperature. -Sud- 
den exposure to dampness and cold, especially if the individ- 
ual had reduced the efficiency of the heat-regulating system 
of the body through improper clothing and poor ventilation, 
would produce a lowered resistance in this manner. 

3. Drugs. — Excesses in the use of drugs and alcohol are 
well known and important in increasing the susceptibility to 
tuberculosis. The factors involved here may be the lowering 
of the temperature, the destruction of delicate defensive sub- 
stances in the body and the inhibition of leukocyte activity. 

5. Undereating". — Insufficient and unsuitable food accel- 
erates tuberculosis. This may be explained by the fact that 
digestion increases leukocytosis. Moreover, infection is more 
likely to pass through an empty stomach than one where 
acid digestion is rapidly taking place. 

5. Oral Defects. — Bacteria which are growing in decaying 
teeth or in chronically inflamed tonsils are producing poisons 
which continually tax the protective powers of the body and 
therefore make it easier for other infective organisms to enter 
and produce disease. Moreover a dirty mouth, already har- 
boring a variety of bacteria, is a better culture place for 
disease germs than is a clean mouth. Enlarged tonsils and 
adenoids reduce the body vigor by their injurious effect upon 
breathing and nutrition. 

SPECIFIC IMMUNITY 

Specific immunity exists by virtue of certain substances 
(immune bodies or antibodies) present in the blood, which 
prevent or retard the development of the disease in question. 
It may be natural or acquired, general or local. Acquired 
immunity may be active or passive. 

Natural Immunity. — Certain species of animals are immune 
to the diseases which affect other species. For example, the 



ESSENTIAL FACTS OF IMMUNITY 129 

lower animals are immune to many of the communicable 
diseases of man such as cholera, typhoid fever, mumps, measles, 
scarlet fever, yellow fever, malaria, leprosy, etc. Man is im- 
mune to many of the diseases which attack lower animals. 
There are certain germs, however, which attack many species 
of widely different genera. Examples of this group include 
the organisms of tetanus, malignant edema, anthrax, pus for- 
mation, glanders, plague, rabies, Malta fever, foot-and-mouth 
disease, milk sickness, ringworm, and paratyphoid fever. 

Local Immunity. — Many tissues of the body appear to be 
immune to diseases which do serious damage to other tissues. 
For example, diphtheria does not often extend from the throat 
down the esophagus. There may even be a difference in 
the susceptibility of the same tissue at different periods of 
life. In general, tissues which are well flushed with blood are 
relatively immune. Prompt local reaction frequently saves 
the more remote tissues of the body by holding back the organ- 
isms and in general this is a good indication of immunity. 

Acquired Immunity. — Acquired immunity is specific for 
particular diseases and is not inherited. It may be secured 
by having the disease or artificially induced by the injection 
of a virus or a vaccine. By virus we mean the living organism 
of infection and by a bacterial vaccine the killed organism 
of the infection. It is obvious that the virus must be reduced 
in virulence or introduced in very small quantities while the 
vaccine is less severe and more likely to produce a local re- 
action followed by a brief general reaction. Sometimes sen- 
sitized vacccines are produced by mixing the bacteria with the 
specific antibodies from the blood serum of an animal which 
has been rendered immune. Polyvalent vaccines are made up 
from several strains of the same organism. Mixed vaccines 
containing the dead bacilli of two or more diseases like ty- 
phoid, paratyphoid and cholera are sometimes used. Immun- 
ity acquired through the use of vaccines usually lasts from 
two to five years. 



130 HYGIENE: DENTAL AND GENERAL 

Active and Passive Immunity.— The above description re- 
fers to active immunity. In other cases the immunity may be 
passive or mixed. In diphtheria the horse from which anti- 
toxin is secured is rendered immune to the disease by the in- 
jection of increasing doses of diphtheria toxin and his immun- 
ity is active. The patient may be made temporarily immune 
by the injection of immune substances from the blood serum 
of the horse. This immunity is passive or transferred and is 
of brief duration. Mixed immunity is produced by injecting 
immune substances from another animal with the vaccine or 
toxin as exemplified in the use of plague vaccine with plague 
antitoxin or in the use of a toxin-antitoxin mixture to im- 
munize against diphtheria. 

'Carriers. — Usually after a disease the body rids itself en- 
tirely of the germs. Occasionally, however, this does not 
happen and a condition of mutual tolerance is set up. This 
' ' immunity without disinfection M is a condition in which the 
patient continues to be a carrier of the germs. The reaction 
between the patient and the infective organism is not serious. 
They have acquired the ability of tolerating each other, and 
the reaction by each has apparently become milder. Carriers 
are found in diphtheria, typhoid, cholera, epidemic cerebro- 
spinal menengitis, influenza and in certain protozoan diseases 
like malaria. Many epidemics have been traced to such car- 
riers. There is always a possibility of a spread of the disease 
in this fashion and in some instances the lowered vitality of 
the individual may result in a relapse of his own case. 

Disease Reactions. — Just as different agricultural plants 
grow best in different soils, select somewhat different foods, 
and produce different products, so the germs of disease vary 
in the part of the body which they attack and differ in their 
life processes and in the effects they produce upon the indi- 
vidual. The actions and reactions between the various mi- 
crobes and man are numerous and complex. This is not the 
place for an extended discussion of them ; but they have such 
an important bearing upon. our comprehension of disease and 



ESSENTIAL FACTS OF IMMUNITY 131 

the terms are so rapidly finding a place in our everyday vo- 
cabulary that a brief description of the terminology and phe- 
nomena may be found useful to the dental student and prac- 
titioner. We shall therefore consider briefly the nature of 
the struggle waged during the course of an infectious disease. 

Toxins. — There are two types of bacterial jioisons which 
produce disease, exotoxins and endotoxins. The true toxin 
(exotoxin) is defined by Rosenau as "a specific poison elab- 
orated by bacterial metabolism ; it is soluble in water ; poison- 
ous in minute amounts; reproduces the essential symptoms 
and lesions of the disease; acts only after a period of incu- 
bation; and produces antibodies, namely, antitoxin." Such 
toxins are complex chemical substances probably belonging 
to the higher proteins. They are thermolabile and unstable. 
Three such substances are well known, the toxins produced in 
diphtheria, tetanus, and botulism. Other bacteria, such as 
dysentery, pyocyaneus and cholera produce soluble toxic sub- 
stances which do not, however, have all the above named char- 
acteristics. 

We should add that many bacteria produce poisonous sub- 
stances of another type such as ferments, ptomains, acids, 
alkalis, nitrites and hydrogen sulphid. The bacilli of tuber- 
culosis and glanders form soluble toxic substances which are 
specific but (in small quantities) harmless in a normal animal, 
being poisonous only to an animal suffering with the specific 
disease. 

There are also toxins from the higher plants such as ricin 
from the castor bean and abrin from the jequirity bean. These 
so-called phytotoxins comply with the above definition of a 
true toxin in most respects. The venoms produced by w r asps, 
scorpions, spiders, and snakes are very similar substances. 

In the case of the true toxin it is impossible to say whether 
it is a secretion or an excretion or the result of the action of 
the bacteria upon the medium. There are four important 
characteristics of these toxins. They are destroyed by boiling 
or by heating at 63 degrees C. for a short time. They are 



132 HYGIENE: DENTAL AND GENERAL 

extremely poisonous in small quantities (0.000,000,05 of a 
gram of tetanus toxin is sufficient to kill a mouse). They 
produce their effect after an incubation period and have a 
specific combining affinity for particular cells of the body. 

Endotoxins. — Certain bacteria contain internal poisons 
which may be liberated when the bacterial cells die. It is 
possible to obtain endotoxins by grinding the cells of the 
dysentery bacillus and the cholera vibrio. "We should not 
conclude, however, that endotoxins are similar in their action 
and composition to true or exotoxins. It may be moreover 
that the split protein products of the bacteria themselves act 
as poisons to the body cells. 

Reactive Phenomena. — The body has been found to react in 
definite ways to particular diseases and our knowledge of the 
basis of immunity rests upon the study of these phenomena 
which include (1) phagocytosis, (2) anaphylaxis, and (3) 
the production of specific substances like antitoxins, opsonins, 
lysins, precipitins, and agglutinins. 

1. Phagocytosis. The important work of Metchnikoff in 
the study of immunity showed that certain bacteria are de- 
voured and digested in great numbers by the cells of the body. 
Cells which accomplish this task are of two types: the motile 
cells (white blood cells) and the fixed cells of the connective 
tissue and endothelium. Metchnikoff believed this phenome- 
non of phagocytosis to be the principal bodily activity in 
combating disease and producing immunity. 

These cells are susceptible to chemotactic influences and it 
is conceivable that the attack of a disease might so accelerate 
their activity that at the inception of a second infection the 
invading bacteria might be devoured before the disease could 
be produced. Phagocytosis how T ever is not a complete and 
adequate explanation for immunity unless it is believed that 
the phagocytic cells produce special immune bodies — to be 
considered later. 

Opsonins. — Phagocytosis has beeen found to take place only 
in the presence of certain substances which prepare the bac- 



ESSENTIAL FACTS OF IMMUNITY 133 

teria for phagocytic digestion. These substances, which are 
called opsonins, are normally present bnt may be increased 
by the injection of bacteria or a specific antigen. They com- 
bine with the bacteria and phagocytosis does not take place 
without them. The opsonic index which is used in vaccine 
therapy is the measure of these substances as determined by 
the ''avidity" with which phagocytic cells devour the bac- 
teria. 

2. Anaphylaxis. — Anaphylaxis or hypersusceptibility is a 
condition of the body in which it is unusually susceptible to 
foreign proteins. This is a specific reaction which may be 
developed against certain bacteria or other protein substances. 
It may be congenital or acquired, local or general 

An example of anaphylaxis as produced by an ordinarily 
harmless substance is secured by the injection of horse serum 
into a guinea pig. If the second injection of serum is sepa- 
rated from the first by an interval of eight to fourteen days 
it produces what is known as acute anaphylactic shock. The 
guinea pig becomes restless, manifests difficulty in breathing, 
is generally agitated and discharges both urine and feces. 
There may soon follow complete paralysis, the arrest of 
breathing, and death. The guinea pig is apparently much 
more susceptible to this reaction than any other animal. The 
explanation of this fact and the phenomenon itself is fur- 
nished by Schultz who showed that serum anaphylaxis pro- 
duces the hypersensitization of smooth muscle tissue which 
contracts during shock with the fatal results, in the case of the 
guinea pig, because the mucosal layer of its secondary bronchi 
is thrown into folds by the contraction of this muscle and 
breathing is inhibited. This reaction is strictly specific. 

By examples of other types of anaphylaxis it may be seen 
how this increased sensitivity of the tissue to particular germs 
may produce a very prompt reaction which may be connected 
with acquired immunity. In the second vaccination for small- 
pox the incubation period is' much shorter and in the prompt 
"take" the reaction is less severe. It appears in this case 



134 HYGIENE: DENTAL AND GENERAL 

that immunity is not complete but the protection is dependent 
upon anaphylaxis. In other diseases this prompt reaction 
may prevent the development of the clinical symptoms. 

In guinea pigs such a sensitization may be produced by 
feeding them meat or serum and the mother guinea pig may 
transmit a hypersensibility to the toxic action of horse se- 
rum to her young. We may raise the question as to whether 
these facts may not explain why symptoms like those in ana- 
phylactic shock sometimes follow the eating of fish and other 
articles of diet and whether this phenomenon explains a pos- 
sible inherited susceptibility to tuberculosis. 

The serum sickness, which often takes place from 12 to 14 
days after the injection of antitoxic sera and shows symptoms 
of fever, itching and pain at the point of injection and a 
general urticaria, may be the anaphylactic reaction from these 
substances still remaining in the body at the end of the incu- 
bation period. The substances which produce serum sickness 
however are the proteins of the horse serum and not the anti- 
toxin itself. 

In considering other examples of anaphylaxis it is to be 
noted that in most febrile diseases there is a ten to fourteen 
day incubation period before the general bodily reaction 
marks the beginning of the active period of disease. Diphthe- 
ria or other diseases where soluble toxins are produced obvi- 
ously do not belong in this class. Tuberculin (a glycerine 
extract from tubercule bacilli) is not poisonous to a healthy 
individual but produces a definite reaction in a tuberculous 
individual because he has become anaphylactic to the disease. 
This test for hypersusceptibility, therefore, may be used in 
detecting the disease. It may also be seen that the hypersus- 
ceptibility of the tissue produces a prompt reaction which 
helps to encapsulate the organisms. 

It has long been known that in many people fish, tomatoes 
and cheese are likely to produce an urticarial rash; eggs may 
produce asthmatic symptoms; and cereals, pork and milk may 
produce erythemas, These cases and many cases of eczema 



ESSENTIAL FACTS OF IMMUNITY 135 

may be due to anaphylactic reactions to the special proteins. 

Anaphylaxis in hay fever is the hypersusceptibility of the 
nmcoiis membrane of the respiratory tract to the pollen of 
ragweed, golden rod and other plants. Dust emanations from 
horses or other animals or hyper acidity of the gastric juice 
may produce similar conditions. Puerperal eclampsia, the 
onset of labor, and the crisis in pneumonia have been in part 
explained by the phenomena of anaphylaxis. 

3. Specific Substances. — Antitoxins. — Antitoxins are sub- 
stances formed in an animal by the stimulation of specific 
toxins. They are capable of neutralizing the corresponding 
toxins. They are substances of complex chemical composi- 
tion, more stable than toxins although destroyed by heat, acids 
and many other chemicals. These substances appear in the 
blood and in all the fluids and excretions of the immune ani- 
mals. AVhen they are introduced into the body, as in the use 
of diphtheria antitoxin from the horse, they disappear rather 
quickly, uniting with the toxin or with the body cells but 
mainly finding exit through the urine, bile and saliva in the 
form of antitoxin. Passive immunity therefore is transient 
and lasts usually from ten to fourteen days while active im- 
munity is of much longer duration. Antitoxins are not always 
produced as a reaction to bacterial toxins even in susceptible 
animals. A guinea pig which is highly susceptible to diph- 
theria will not produce any antitoxin. 

It can be shown that there is a direct union between anti- 
toxin and toxin by mixing the two in a test tube and then 
injecting the mixture into a susceptible animal. This injec- 
tion produces no observable or injurious result. After the 
toxin has once been united with the body cells however it 
cannot be dislodged by an antitoxin. It may thus be seen why 
moderate amounts of diphtheria antitoxin in the earlier stages 
of the disease are more efficacious than large doses adminis- 
tered at a later period. Antitoxin may be present in the blood 
before infection takes place, 



136 HYGIENE: DENTAL AND GENERAL 

Agglutinins. — Widal showed that very dilute mixtures of 
the blood serum of a typhoid patient will cause the typhoid 
bacilli to agglutinate, that is, to lose their motility and gather 
in little clumps. These small groups may be seen under the 
microscope or as flakes in a test tube suspension. It was later 
found that agglutinating substances may be produced in the 
blood by injecting dead bacteria into the body, as in typhoid 
vaccination. 

Agglutination does not harm the bacteria by rendering them 
motionless. They may again multiply and grow vigorously. 
The so-called germicidal property of freshly drawn milk is 
probably mainly a phenomenon of agglutination, since the 
bacteria are clumped together and only one colony for each 
clump of organisms is developed on the agar plate. 

Agglutinins are not absolutely specific since, if they are 
used in large quantities, closely allied species of bacteria may 
also be agglutinated. They are however, quantitatively spe- 
cific, since the corresponding organisms will be agglutinated 
by a greater dilution. Agglutination may also be produced 
for red blood corpuscles and protozoa. The part which these 
substances play in immunity is not yet clear. 

Precipitins. — In 1897 Kraus showed that it is possible to 
produce another type of immune body in the blood serum of 
an animal by the injection of bacteria or albuminous sub- 
stances. When the clear serum of an immunized animal was 
added to the clear antigen the resulting fluid became opaque 
from the formation of a precipitate which soon settled to the 
bottom of the test tube. This discovery was made by adding 
some typhoid serum to a filtered culture of typhoid bacilli. 
Certain other organisms like cholera and plague produce the 
same phenomenon but not all bacteria do this and the diph- 
theria bacillus is the important example of the latter class. 
This precipitation is similar to the agglutination of bacteria 
and is a reaction of protein molecules which, as we know, are 
not true solutions but colloidal suspensions. The relation of 
these substances to immunity is not clear but we may see how 



ESSENTIAL FACTS OF IMMUNITY 137 

it may be possible for them to throw down poisons from solu- 
tion and make them inert. 

Lysins. — In 1896 Dr. Pfeiffer observed that when living 
cholera vibrio were injected into a peritoneal cavity of guinea 
pigs which had been previously immunized against cholera the 
germs lost their power of motion, became grouped together in 
clumps and were finally completely dissolved. This reaction 
which is specific for special diseases is known as Pfeiffer 's 
phenomenon, and the substances which have the power of 
disintegrating or dissolving cells or other organized substances 
introduced into the body are called lysins. Those which dis- 
integrate bacteria are called bacteriorysins, those which dis- 
solve the red blood corpuscles of other animals are called 
hemolysins, and those which dissolve the cells of glandular 
tissues are called cytolysins. The normal bacteriolytic proper- 
ties of the blood are thought to be due almost entirely to a 
similar nonspecific substance which dissolves the various bac- 
terial cells. It is this power which enables the blood to resist 
decomposition longer than other animal fluids. 

That the complete explanation of immunity is not furnished 
by the lysins is shown by the fact that animals may be sus- 
ceptible to disease although the blood possesses bactericidal 
properties. In anthrax the rabbit is very susceptible although 
the blood serum is highly bactericidal, while the dog is very 
resistant although the blood is slightly bactericidal. 

Bacteriolysins are distinct from antitoxins and agglutinins. 
The three substances may be distinguished from one another 
by proper tests even when they exist together. The lysin is 
composed of two substances, the immune body which prepares 
or sensitizes the bacteria and the complement which dissolves 
the bacteria. The complement appears to be formed by the 
breaking down of leukocytes and is present in normal blood. 
Although present in the blood it is absent in the aqueous 
humor of the eye because the latter lacks leukocytes. It is the 
immune body or amboceptor which is specific for particular 
diseases and which is increased as immunity is built up. 



138 HYGIENE: DENTAL AND GENERAL 

Hemolysis or the laking of blood is the dissolving of hemo- 
globin from the red blood corpuscles. There are two types 
of hemolysins: (1) the nonspecific such as distilled water, 
acids, alkalis and bacterial, plant and animal toxins, and (2) 
the specific hemolysins which are obtained by treating or im- 
munizing the animal with the red blood corpuscles of another 
species of animal. Hemolysins of the latter type are similar 
to bacteriolysins. 

It has been stated above that the amboceptor is specific while 
the complement is nonspecific. The complement fixation test 
used in the diagnosis of syphilis, gonorrhea, glanders, per- 
tussis, meningitis and other infections is based on this prin- 
ciple. 

THEORIES OF IMMUNITY 

It should now be apparent that infectious diseases and 
bodily reactions to these diseases are widely different and 
that no simple theory of immunity can be satisfactory. It 
is therefore, only with historical interest that we regard the 
early theories of Pasteur and Chauveau. 

Exhaustion Theory. — In 1888 Pasteur suggested his ex- 
haustion theory which held that immunity was produced be- 
cause all the food substances were used up. The one fact that 
bacteria may grow in the dead tissues of immune animals 
shows that, during the life of the animal, their growth is in- 
hibited by specific substances and not by lack of food. 

The Retention Theory.— The retention theory of Chauveau 
maintained that bacterial growth was inhibited in disease by 
the retention of the products of bacterial metabolism. It is 
not difficult to demonstrate the fallacy of this view. 

Phagocytic Theory. — The work of Metchnikoff in demon- 
strating the activity of phagocytosis suggested a possible 
mechanism of immunity. It could be demonstrated that the 
phagocytic powers of an animal increased directly with its 
immunity and Metchnikoff asserted that it was the increased 
activity of the white blood cells which produced immunity. 



ESSENTIAL FACTS OF IMMUNITY 139 

\Ve have seen in the development of opsonins the influence of 
the body fluids upon phagocytosis. 

These views were opposed by Ehrlich and other investigators 
who believed immunity to be due mainly to substances pro- 
duced in the body and set free in the body fluids. From their 
point of view phagocytosis was merely the process of getting 
rid of bacteria after they had been acted upon by the immune- 
body substances. Aietcknikoff realized the existence of these 
substances in the body fluids but he believed them to be de- 
rived from the leukocytes. The question is by no means set- 
tled and there is much evidence to support the great import- 
ance of phagocytes in bacterial immunity. 

Side Chain Theory. — Every student of organic chemistry 
is familiar with the term side chain as applied to the atomic 
groups attached to the benzol ring. The graphic formula for 
benzene is : 

H 

C 

H-C/\C-H 

I I 

H-C\/C-H 

C 

H 

This central structure is possessed by a large number of com- 
pounds. For example salicylic acid has the following formula : 

C-OH 
K-C/\C-COOH 

I I 

H-C\/C-H 

C-H 

The Oil and COOH groups are side chains through which 
other substances and new atomic groups max- enter into rela- 
tionship with the benzol ring. 

The side chain theory of immunity, which was developed by 
Ehrlich, is a theory of chemical side chains which are attached 
— not to a simple ring as in the benzol group — but to a central 
atom group of the large and complex proteins which make up 
cell structures. 



140 HYGIENE: DENTAL AND GENERAL 

In 1885 Ehrlich had stated his belief that the cells of the 
body take on nutrition through the reaction of side chains, 
from the central protein molecules, with the various nutritive 
substances in the circulating blood. It seemed reasonable to 
him, therefore, that toxin might exert its injurious influence 
upon the cells of the body by combining with certain chains of 
the cell protein. Certain of these side-chains might have a 
specific affinity for a particular poison. When this union had 
taken place, however, the side chains would be destroyed. 

Now it is characteristic of nature to regenerate parts of 
tissues which are lost and such regenerative processes are al- 
most always carried to excess. A good example of this is seen 
in the excessive production of bony substance after a fracture. 
It seemed reasonable that, in this case, nature might produce 
an excessive number of side chains or receptors under the con- 
tinued stimulation and if this were done some of them would 
be thrown off into the blood where they would be free to cir- 
culate and unite with the poison before it could reach the 
sensitive cells. "With such a substance (antitoxin) in the 
blood a new infection would not produce the clinical symptoms 
of disease and the person would be immune from the disease 
in question. This type of immunity is spoken of as immunity 
of the first order and is illustrated in the explanatory diagram. 

We have seen that the body may possess different kinds of 
immune reactions as exemplified by the power of blood serum 
to agglutinate and precipitate such disease germs as those 
of typhoid fever. The bacterial substance which injures the 
human body in this case is not a soluble substance, but a 
complex molecule of the bacterial protoplasm. It seemed to 
Ehrlich that the immune bodies in this type of reaction must 
be more complex than the receptors described above. Side 
chains which are capable of handling these albuminous sub- 
stances he conceived to have not only a combining (hapto- 
phore) group, for anchoring the substance to the body cells, 
but also a ferment (or zymophore) group which could break 
down the complex molecule after it was anchored. The agglu- 



ESSENTIAL FACTS OF IMMUNITY 



141 



J~ 




-zr 



-<5kwfe//'cz/ C7<?// 





<J 



JBOC7i?/7o/ &■«•// 

\ A ) 



jzt 



^3&c-/e/7t7/ c<?/ 




X 



^oc/er/c?/ ere// 




Fig. 20. — Diagram illustrating the three orders of immunity as described in Ehr- 
lich's Side Chain Theory of Immunity. 

I. Immunity of the first order. 1. Inciting substance (toxin). 2. Immune 
substance (antitoxin). (b) Shows antitoxin which has been absorbed into 
the blood stream from the diphtheritic throat. The toxin molecule is seen ap- 
proaching the side chain. (c) By the excessive production of side chains anti- 
toxin is thrown off into the blood. (d) The antitoxin unites with the toxin in 
the blood preventing the latter from attacking the living cells. 

II. Immunity of the second order. 1. Inciting substance (antiagglutinin, anti- 
precipitin, etc.). 2. Immune substance (agglutinin, precipitin etc.). The immune 
substance in this case shows a haptophore group (joining end) and a zymophore 
group (portion containing an enzyme), (a) Bacterial cell with inciting substance in 
the blood (b) inciting substance about to combine with side chain of body cell. 
.(c) Free antibody in the blood and combination of inciting substance and anti- 
body (precipitin reaction). (d) Antibody combining with inciting substance in 
the bacterial cell (agglutination). 

III. Immunity of the third order. 1. Inciting substance (anti-immune body). 
2. Specific immune body having a cytophile group which combines with the in- 
citing substance and a complementophile group which combines with the comple- 
ment. 3. Complement or nonspecific immune body free in the blood. (a) 
liacterial cell with inciting substance, (b) Inciting substance about to unite with 
side chain (amboceptor). (c) Immune bodies and bacterial cell free in the 
blood, (d) Union of three bodies in bacteriolysis. 



142 HYGIENE: dental and general 

tinating power of the blood of an immune individual lie con- 
ceived to be due to the presence of these receptors of the 
second order which would be thrown off into the blood under 
continued stimulation, like the antitoxin type of receptor. 
This immunity of the second order is also illustrated diagram- 
matically. 

The process of bacteriolysis which has an important bearing 
on immunity is of a different nature than the two phenomena 
just described. Students of this phenomenon found that the 
normal blood of animals has the power of killing certain 
disease germs to a limited extent, and that the blood of specifi- 
cally immune animals has the power of killing and dissolving 
the particular organism for which the animal is immune to a 
great degree. It was also learned that the blood of an immune 
animal loses this power upon being heated to 56° C. but that 
the power is regained by the addition of a little normal serum 
from a nonimmune animal. Reasoning from these data Ehr- 
lich assumed and later proved to his own satisfaction that, in 
this type of immunity, there is a nonspecific dissolving sub- 
stance (complement) in the normal blood which is able to act 
upon the bacteria only in the presence of and by combining 
with specific side chains produced by the cell proteins in a 
manner similar to the way the above mentioned receptors are 
produced. The side chain of the body cell in this third type 
of immunity has two receptive parts. When such side chains 
or receptors are thrown out into the blood they unite with 
both the reactive substance of the germ cell and with the com- 
plement, which, acting through these receptors, is able to dis- 
solve the bacterial substances. A similar reaction takes place 
when the body is immunized to foreign blood or other cells. 
Part three of the diagram shows the nature of this third order 
of immunity. 

In all of the above-mentioned orders the immunizing sub- 
stances are supposed to be produced by the body cells and 
they appear in the blood by the excessive regeneration of 
those first destroyed by the bacterial poison. The immune 



ESSENTIAL FACTS OF IMMUNITY 143 

substances of the first order, when they are free in the blood, 
are spoken of as antitoxins, those of the second order are 
precipitins or agglutinins, those of the third order are called 
amboceptors. 

Vaughan has shown (Protein Split Products, Lea and Febi- 
ger, 1913) that split protein products from most proteins will 
produce a fever reaction if injected into the body systemati- 
cally. Such substances are produced by almost all bacteria. 
It is a question whether the fever reaction produced by such 
organisms as the typhoid bacillus may not be due to these 
split proteins by a sort of consecutive anaphylactic poisoning 
rather than by specific endotoxins. 



CHAPTER VIII 

ORAL PROPHYLAXIS 

In the chapter on the Hygiene of the Mouth we discussed 
the normal development and use of the oral structures in 
health. Here we are concerned with the prevention of septic 
and disease processes. 

Caries. — All the pathological conditions of the dental pulp 
— calcareous deposits within these tissues excepted — and the 
series of morbid processes leading to the formation of alveolar 




Fig. 21. — Deformity resulting from neglect of the teeth. 



abcess are due (except in the case of traumatic injury) to the 
infection of this organ from the inroads of caries. The sub- 
ject of dental caries has engaged the attention of scientific 
minds for more than four hundred years, and although much 
has been accomplished towards the solution of the problem, 
yet it still affords an ample field for laboratory research. 

In 1530 a German writer published a statement so closely 
in accord with modern findings as to be prophetic of the later 
work of Miller and others. The following is a translation 
taken from Black's Operative Dentistry. 

144 



ORAL PROPHYLAXIS 



145 



Caries is a disease and evil of the teeth in which they become full 
of holes and hollows, which most often affects the back teeth; especially 
so when they are not cleaned of clinging particles of food which de- 
compose, producing an acid moisture which eats, them away and destroys 
them so that finally with much pain they rot away little by little. 

Prior to the work of John Tomes, who gave to the world in 
1860 the results of his microscopical studies of dental tissues, 
but little was known of the histological structure of the teeth, 
and caries was generally regarded as an inflammatory process, 
having its origin within the dentin of the tooth affected. 




Fig. 22. — The case seen in Fig. 21 showing the malocclusion due to caries. 

Tomes found that the structure of dentin was such that a true 
inflammation was impossible, there being no circulatory sys- 
tem. (An exception to the generally accepted opinion, prior 
to Tomes, is found in that of Robertson, who, in 1835, ex- 
pressed the opinion that caries resulted from the action of 
acid due to the decomposition of particles of food retained in 
fissures and imperfections of the teeth.) 

In 1857 Leiber and Rotenstein in the course of experimenta- 
tion found that carious dentin, when stained with iodine, dis- 
closed within the tubules granular bodies which were recog- 



146 hygiene: dental and general 

nized as bacteria. This is the first record of the association 
of bacteria as a cause of caries. Miles and Underwood in 1881 
fonnd that two factors were always active in caries, namely 
(1) the action of acids, (2) the action of germs. 

Miller in 1882 announced the results of experiments con- 
ducted by him. His experiments were carried on with a view 
of solving the problem of. caries of dentin, but little light 
was thrown on the problem of the initial lesion in the enamel. 

His conclusions briefly stated are as follows : 

(1) Microorganisms are always present in the tubules of 
carious dentin. 

(2) The invasion of the tubules is preceded by decalcifica- 
tion of the dentin. 

(3) The fermentation of carbohydrate foods by mouth bac- 
teria produces lactic acid. 

(4) Lactic acid causes decalcification of the dentin, this 
process being followed by the decomposition of the organic 
matrix. 

Caries of enamel is undoubtedly due to the same phenomena 
that are operative in caries of the dentin. It differs in some 
particulars, as follows: 

(1) The original foci of decay are generally found in dis- 
tinct and definite locations. 

(2) The location of each focus of decay is in a position 
favorable to the retention of food material. 

(3) The food material retained in this location in the pres- 
ence of warmth and moisture, affords a culture medium for 
acid forming bacteria. 

(4) The undisturbed confinement of the acid formed in 
the fermentative process is sufficient to dissolve the enamel. 

Why this carious process is active in some mouths and 
passive in others equally neglected remains undecided. It 
may be that in the normal secretions of some mouths there are 
substances capable of holding in abeyance the development of 
bacterial flora. It' may be that through the refinement of 
food material and the development of epicurean tendencies, 



ORAL PROPHYLAXIS 1-47 

which eliminate the necessity for vigorous exercise in mas- 
tication, the stimulating effect upon the secreting glands with 
the neutralizing action of a copious flow of saliva is lost. 
Or perhaps the solution of the problem lies in the resistance of 
the enamel itself due to its composition and density. Slight 
imperfections in the structure of the enamel are almost in- 
variably present, thus making the dentin easy of access to 
the fermentative bacteria of the mouth. 

Howe in his research work on caries at the Forsyth Dental 
Infirmary found that a few species of highly aciduric micro- 
organisms were responsible for the carious process. He ob- 
tained these findings by first sealing carious cavities with 
cement, thus separating the carious material from the flora 
of the mouth. The bacterial cultures were later secured from 
the layer of carious dentin which had been thus isolated. 

Although the problem of caries has been seemingly solved 
by the work of Miller and others, yet there are undoubtedly 
factors related to the question of immunity which are not 
yet understood; and it may be that nutrition plays a larger 
part than we now comprehend. 

Diet in Relation to Decay. — Inasmuch as the protective 
covering of the teeth is fully completed at the time of erup- 
tion, too much stress cannot be laid upon the building up of 
these tissues or upon the diet of children up to the twelfth 
or thirteenth year. What constitutes a well-balanced diet is 
still a problem for research, but in viewing the subject from 
the standpoint of common sense it would seem that a study 
of the diet of the more primitive races, among whom normal 
development of the teeth is practically universal and who 
maintain the integrity of the teeth during the period of great- 
est susceptibility, would be illuminating. 

The most universal food and the one containing in itself 
all of the three nutritive constituents, viz., proteids, carbo- 
hydrates and fats, is milk. Milk is also the richest of all 
articles of diet in the calcium content, this being the element 
of greatest importance in the development of the bones and 



148 HYGIENE: dental and general 

teeth. A liter of milk contains iy 2 grams of lime, which 
is a larger quantity than is contained in a similar amount of 
lime water. 

The mineral content of milk is sufficiently high to give it 
the first place as a bone building food, and as the teeth re- 
quire practically the same elements for their proper develop- 
ment it is of equal importance as related to them. The infant 
requires about one-third gram of lime daily and this amount 
is supplied in milk. A deficiency in lime may lead to soften- 
ing of the bones and imperfect development of the teeth. 
Next to milk come eggs, then the cereals and then certain 
vegetables such as carrots, asparagus and spinach. So neces- 
sary are these mineral substances in maintaining the fabric of 
the various tissues that death ensues if the supply is entirely 
cut off, even though the other constituents of diet are sup- 
plied in normal amount. The refining process to which many 
of the cereals are subjected in the manufacture of flour has 
the effect of depriving the grain of its mineral substance. 

The mineral content of foods during gestation should be 
carefully considered in the dietary of the prospective mother, 
as the proper nutrition of the developing fetus is essential in 
the formation of enamel. On the other hand the development 
of the dentin, cementum and alveolar process takes place in 
a large measure after birth and continues throughout the life 
of the individual. Hence proper nutrition in infancy and 
later life is essential for the upbuilding of these tissues. 

I would lay great stress on the habitual use at each meal 
of foods selected not only on account of the nutrient quali- 
ties, bat also because they require sufficient masticatory effort 
to make vigorous exercise necessary in the performance of 
this function. The benefits of thorough mastication have been 
popularized by Mr. Horace Fletcher until Fletcherism has 
become a household word, and I am convinced that the bene- 
ficial results are more far reaching than even the most ardent 
advocate realizes. In the first place there is an invigorating 
effect upon the supporting structures of the teeth. Vigorous 



ORAL PROPHYLAXIS 



149 



mastication gives the necessary- stimulation to the peridental 
membrane, which being richly supplied with blood needs this 
stimulation and functional activity for the maintenance of 
tone. There is an increase in the flow of saliva and exercise 
is afforded for the muscles of mastication. The passing of the 
food materials over the teeth cleanses their various surfaces 
and massages the gums and gingivae. 

The Care of the G-ums and Gingivae. — Black has divided 
the investing tissues of the mouth into two classes. First, 




Diagrams illustrating nomenclature of gingivae. (Black.) 

Fig. 23. — Buccolingual section through tooth and investing tissues. .A, Alve- 
olar process; A 1 , Crest of alveolar process; G, Gum; B, Body of gingiva; F, 
Free gingiva; C, Crest of gingiva; Sg, Subgingival space. 

Fig. 24. — Mesiodistal section through first and second bicuspids and septal 
tissue. A, Alveolar process; A 1 , Crest of alveolar process; B, Body of gingiva; 
S, Septal gingiva; C, Crest of septal gingiva just below contact point; Sg-Sg, 
Subgingival spaces. 

the gums which clothe the alveolar process and hard palate, 
second, the gingivae, which invest the cervical portions of the 
teeth; it is the latter which exercise an important protective 
function and play an important part in the prevention of 
disease ; for it is in these tissues that the initial injury occurs 
which, if neglected, frequently leads to the infective process 
commonly known as Pyorrhea Alveolaris. 

The gingivae completely encircle the teeth passing over the 



150 hygiene: dental and general 

crest of the septum, of the alveolar process and rising to a 
point just below the contact point between the proximal sur- 
faces of the teeth. The crests of the gingivae are not attached 
to the teeth but in health closely hug the portion which they 
encircle. The immunity to decay of the area of the teeth 
covered by this free gingiva is attributable to the perfection 
of its form and structure; it fits closely every part of the 
tooth, filling the interstices and guarding the tissues beneath 
from injury. 

Insufficient study has been given to the function of these 
tissues and occasionally even the dentist, in the performance 
of restorative operations upon the teeth, has been negligent 
in his care of these delicate structures. There can be no 
doubt that in such cases he was responsible for the initial 
injury, which ultimately developed into a suppurative inflam- 
matory process leading to the destruction of the investing tis- 
sues and to the eventual loss of the teeth. The hygiene of the 
gingivae should command the closest attention of the dentist, 
and the cooperation of the patient. In many cases the removal 
of the serumal deposit from the surface of the tooth immedi- 
ately under the free gingivae will be sufficient to relieve the 
inflammation. This treatment should be followed at stated 
intervals by gentle massage with the finger; the stimulation 
to the circulation will be sufficient to restore these tissues 
to a normal state of health and resistance. The gingivae 
should receive treatment in every performance of the toilet 
of the mouth and teeth. Gentle stimulation by proper brush- 
ing goes far to maintain firmness of texture and freedom from 
circulatory congestion, the prime factors in the health of the 
supporting structures of the teeth. 

Inflammation of the gingivae frequently is caused by injury 
from the crowding of food material into the interproximal 
spaces on account of faulty proximal contact due to malposi- 
tion of the teeth or loss of proximal contact from the begin- 
ning of decay. The impacted food material first presses away 
the septal gingiva?, following this, putrefaction and fermenta- 



ORAL PROPHYLAXIS 151 

tion take place. The soft tissue thus infringed upon and 
injured, loses its tone and becomes an easy prey to the micro- 
organisms of infection. When the septal gingiva is pressed 
down by the impaction of food material a pocket is formed, 
and an infection of the underlying structures soon takes place. 
The peridental membrane covering the root of the tooth is 
invaded and destroyed and its loss is followed by infection 
of the porous cementum covering the dentin of the root. In- 
fected cementum, unlike necrotic bone, will not separate itself 
from the healthy tissue and nature has made no provision for 
its repair after the loss of the peridental membrane. It 
therefore becomes a dead septic area insusceptible to remedial 
treatment. 

If the destruction of the peridental membrane is limited 
in extent, it may be possible by proper instrumentation to 
remove the septic portion and establish a new line for both 
the gum and peridental membrane ; then by the exercise of ex- 
treme care by the patient and frequent attention by the den- 
tist the progress of the destructive process may be checked. 

Gingivitis. — The early recognition of the presence of a 
congested condition of the gingivae and intelligent remedial 
treatment are fundamental in mouth hygiene. Only the trained 
observer will be able to do this, as the indications are so 
slight as to .elude even such a one, unless the closest examina- 
tion is made. These examinations must include a study of oc- 
clusion, contact points, and deposits. The removal of deposits 
and the correction of contact or the removal of occlusal strain 
will generally be sufficient to eliminate the sources of irrita- 
tion. This treatment must be supplemented by personal care 
on the part of the patient who should be instructed in regard 
to t lie means available for permanently maintaining circula- 
tory activity in these tissues. Back of all this is the function 
of nutrition. These means include thorough mastication, 
proper brushing of the teeth and massage of the soft tissue. 
Failure to treat these conditions in their incipiency frequently 
results in the establishment of chronic inflammatory condi- 



152 HYGIENE : DENTAL AND GENERAL 

tions, disastrous in their results. Prophylactic treatment of 
the gingivae is as important as prophylaxis applied to the 
teeth. 

Deposits. — Black has shown that an excess of calcoglobu- 
lin is thrown into the mouth with the saliva after the ingestion 
and assimilation of palatable food eaten of heartily. The 
deposits are paroxysmal, occurring at regular periods after 
eating. They become attached to any irregular surface in the 
immediate locality of the ducts of the salivary glands. It 
was possible to stop or produce deposits at will by the regula- 
tion of diet, eating to excess always produced a deposit. The 
deposit is at first very soft, and spreads over the surface 
of the teeth. It may be easily removed by careful brushing, 
the only difficulty being the inaccessibility of its position; 
but it may be reached if sufficient care is taken. It is neces- 
sary to explain to the individual the usual location of these 
deposits in order that he may intelligently effect their .re- 
moval. 

Another form of calcareous deposit, which has been termed 
serumal calculus, occurs in locations inaccessible to the saliva, 
the more common location being under the free margin of the 
gum and on the cementum of the roots of the teeth. The 
deposits are probably the result of an effusion of serum heav- 
ily laden with calcoglobulin resulting from inflammation of 
the gingival tissues. They seldom occur in the mouths of chil- 
dren. They are an additional source of irritation to the sup- 
porting tissues of the teeth and should be removed. As it is 
seldom possible to prevent their accumulation frequent exam- 
ination by the dentist is necessary. The surfaces of the teeth 
should be freed from deposit and polished, great care being 
taken not to injure the gingiva or to detach its connection with 
the cementum of the tooth. Prophylactic treatment by instru- 
mentation and polishing in the mouths of children should be 
done with extreme care and in many instances it is not indi- 
cated at all. 



ORAL PROPHYLAXIS 153 

Prophylactic Treatment. — The great benefits to be de- 
rived from prophylactic treatment of the teeth and gingiva) 
were first brought to the attention of the dental profession and 
public by Dr. D. D. Smith of Philadelphia, who was able to 
demonstrate that dental caries in a large percentage of indi- 
viduals is preventable. His treatment consisted in frequent 
polishing of the surfaces of the teeth with suitably shaped 
orangewood points impregnated with flour of pumice, the 
points being held in a porte-polisher. Patients were required 
to come for treatment as often as necessary, this being in many 
cases weekly or. bi-monthly. Dr. Smith claimed much for this 
treatment, even to the assertion that a thorough massage of the 
teeth actually brought about changes in the character of the 
enamel, that enamel became more dense and highly resistant to 
the action of the destructive elements within the mouth. 

It is quite obvious that in order to carry out the regime of 
Dr. Smith the dentist with a clientele of moderate size would 
be obliged to devote his entire time to the cleansing and pol- 
ishing of teeth and that he would be unable to attend to the 
operations demanding his highest skill. It followed therefore 
that dentists undertaking to carry out this polishing, as a 
regular routine in practice, were obliged to seek aid ; and the 
problem was finally solved by training young women to act 
as assistants. 

The Dental Hygienist. — The legality of employing regis- 
tered assistants for the performance of operations on the teeth 
gave rise to a controversy within the profession which finalty 
resulted in an appeal to the legislatures of the various states 
and in the enactment of laws that placed the practice of oral 
prophylaxis upon a legal basis and created a new and useful 
vocation for women who are known as Dental Hygienists. The 
work of a dental hygienist is carried on in much the same man- 
ner as was originally done by Dr. Smith, some modifications 
and elaborations having been added since that time. 

Through the efforts of Dr. A. L. Fownes, the first School for 
Dental Hygienists was established in 1914. Since that time 



154 



HYGIENE: DENTAL AND GENERAL 




O O 

o o 



UQ 



Gt3 



Jr 

C 



ORAL PROPHYLAXIS 155 

several schools have been organized and are now in operation. 
The Forsyth Dental Infirmary for Children has a training 
school in affiliation with Tufts College Dental School, and 
there is another school at the Rochester Infirmary which was 
established through the benefaction of Mr. George Eastman of 
Kodak fame; and a fourth school at the Dental Department 
of the University of Minnesota. 

The dental hygienist is given a good perspective of the 
field of dental practice and is thoroughly trained in the activ- 
ities which she is to undertake. Not only does she clean 
and polish teeth but in addition she is able to assist in anaes- 
thesia, x-ray work and the preparation of patients for oper- 
ations. 

The recent and rapid development of dental hygiene work 
among school children has created an opening for dental hy- 
gienists in the official health organization of many communi- 
ties. The young woman of proper training and suitable per- 
sonality is extremely valuable in school Avork since her 
enthusiasm and her ability to get on well with children es- 
pecially qualify her for both clinical and educational work. 
She examines the teeth of the children, fills out the dental 
chart indicating the defects and arranges for the visits to the 
school dental clinic. When the child arrives for treatment it 
is the hygienist who allays its fears, prepares the mouth for 
treatment, cleans and polishes the teeth and assists the dentist 
in operative work if this is necessary. Instructions in dental 
hygiene and the conducting of toothbrush drills may devolve 
either upon the School Nurse or the Dental Hygienist. At 
present there are, unfortunately, far too few- graduates in 
Dental Hygiene to supply the demand for such services. 

Daily Care of the Teeth. — We have staled that caries of 
the enamel is largely due to the retention or confinement of 
food material in locations favorable to its remaining undis- 
turbed for a sufficient period of time for fermentation to 
take place. This being the cause of the formation of cavities 
and decay, it is obvious thai if this food material can be 



156 HYGIENE: DENTAL AND GENERAL 

removed before the bacteriological action takes place, the dis- 
solution of the tooth substance will be prevented. With the 
most scrupulous care it is impossible to entirely prevent caries 
in highly susceptible mouths where it is very active, but the 
frequency of occurrence may be greatly lessened. After five 
years ' supervision of the school children in the City of Bridge- 
port, Fones reports that caries has been reduced from 30 to 60 
per cent in the various schools. The children were carefully 
drilled in the use of the toothbrush and home care was in- 
sisted upon. In conjunction with this, frequent prophylactic 
treatment by the dental hygienist was given. 

"We believe that the care of the teeth should begin as soon 
as the child is put upon a mixed diet and even before this if 
there are evidences of accretions upon the surfaces of the 
teeth. The brush should be of suitable size to suit each indi- 
vidual case, not too large to pass between the lip and cheek 
and the surfaces of the teeth, and with bristles neither so stiff 
and resistant as to cut the soft tissue nor so soft as to be in- 
effective in the removal of soft material. Prior to use the 
new brush should be soaked in boiling water. No definite 
method or rule can be made for brushing these teeth. The 
parent or nurse must take care that it is done thoroughly 
without injuring the soft tissues. 

Method of Brushing the Teeth. — The child should be early 
taught to use the toothbrush properly. Whatever method is 
advocated the object is the same, namely the removal of all 
extraneous material and the stimulation of the soft tissues 
without injuring them. 

Fones advocates the following method of brushing : 

Place the toothbrush inside left cheek and on upper gums, and nearly- 
close the teeth together. Make the brush go backward and downward 
to lower gums, then slightly forward and upward until it has traveled 
a complete circle. This circular motion should be done rapidly so that 
the gums will be stimulated and the teeth cleansed of food. 

Keep up this fast circular motion and brush all the teeth on the 
left side as well as all of the front teeth. Do not brush the teeth and 
gums crosswise. 



ORAL PROPHYLAXIS 157 

Now brush the right side with the same circular motion or reversing 
the circle if found more convenient. Brush long enough to thoroughly 
stimulate the gums and cleanse the teeth, going back and forth over 
all the surfaces several times. 

With the bristles of the brush pointing upward and the end of the 
thumb on the back of the handle, brush the roof of the mouth and the 
inside gums and surfaces of the teeth with a fast in-and-out stroke, 
reaching back on the gums as far as you can go. Go back and forth 
across the roof of the mouth with this in-and-out stroke at least four 
times. 

Hold the handle of the toothbrush in your fist with the thumb lying 
across the back of the handle and brush the gums and teeth with an 
in-and-out stroke, using chiefly the tuft end or toe of the brush. Eeach 
back in the mouth on the gums below the last tooth on both sides and 
brush with a fast, light, in-and-out stroke. Tip the handle of the 
brush up in brushing the gums back of the lower front teeth. 

Lastly, brush the teeth with an in-and-out stroke on the surfaces 
on which you chew, as the food must be removed from the grooves or 
fissures of the molars. 

The writer prefers the following method described by 
Black in the chapter on Month Hygiene in his Special Dental 
Pathology. Beginning with the left side of the lower jaw, 
after the brush has been moistened in water or normal salt 
solution and lime water, the end should be carried back to the 
last molar or beyond when possible. The ends of the bristles 
of the brush should be placed against the gums over the roots 
of the teeth. Then with either a straight or twisting motion of 
the wrist the brush should be swept over the teeth toward their 
occlusal surfaces. This should be done several times. The 
same procedure should be repeated with the right side. 

For the upper jaw the brush is placed far back on the gum 
first on the left side. The bristles are swept over the gingivae 
and teeth in the direction of the occlusal surfaces. The same 
procedure is used for the right side. Particular attention 
is called to the fact that the motion of the brush is first over 
the gums, next over the gingivae and next over the buccal 
surfaces of the teeth to the occlusal margins. Then the brush 
is lifted and replaced upon the gums as before and again 
swept over the gingivae and teeth. 



158 



HYGIENE: DENTAL AND GENERAL 



The motions for the lingual surfaces of the lower molars 
should be practically the same as those for the buccal sur- 
faces but they are more difficult to make correctly. The same 
may be said for the lingual surface of the upper molars. In 
brushing of the lingual surfaces of the incisors the handle 
of the brush should project out of the mouth parallel to the 
length of these teeth. The brush held in this position should 
be placed on the gum and the motion of the brush should be 




Fig. 26. — Tooth brushes of proper shape and material are made in different 
sizes for children and adults. The cut shows such tooth brushes exactly one-half 
normal size. 



over the gum, gingivae and teeth. The brush should then be 
lifted and replaced on the gum and the motion over the gum, 
gingivae and teeth repeated several times. The brush may be 
moved from side to side across the lingual surface of the 
teeth close to the gum for removal of deposits which may have 
been missed by the other movements. This brushing should 
include the gum. The occlusal surface of the teeth should also 
be thoroughly brushed. 



ORAL PROPHYLAXIS 159 

The teeth should be brushed with sufficient frequency to 
prevent the fermentation of food with the formation of acid. 
Four times a day has been advocated, once after each meal and 
before retiring at night. The time of greatest importance 
is before retiring; for in sleep the muscular tissues of the 
mouth are at rest and the oral secretions greatly lessened, 
thus affording the most favorable opportunity for undisturbed 
action of the acid-forming bacteria. This final brushing 
should never be neglected. The danger of infection of the 
soft tissues of the mouth by proper brushing is so slight as 
to be practically negligible. 

Care of the Brush. — As the result of experiments to de- 
termine the most hygienic method of caring for the brush 
the authors have found that a brush rinsed in water after 
using and then placed in a closed receptacle developed many 
more bacteria than one which was rinsed in hot water and left 
in the air to dry. It is therefore advised that the brush be 
thoroughly rinsed in hot water after each use. The brush 
should be freed from water as much as possible by shaking 
and then hung in the air in a place protected from the dust. 

Dental Floss. — The use of dental floss is to remove any 
particles that may remain upon the proximal surfaces of the 
teeth after brushing or after eating when it is not possible 
to brush the teeth. The silk should be passed through the 
contact points and held closely to the surface of the teeth 
and carried upward or downward as far as the gingiva?. 
Care must be taken or injury will be done. If the contact 
point is close, the force used may result in the sudden passage 
of the floss and carry it against the soft tissues so roughly 
as to cause damage. 

Toothpicks. — The toothpick is also used to clean the 
proximal surfaces of the teeth after eating. An orangewood 
pick with a smooth flat blade or a quill is to be preferred 
and care should be taken not to injure the soft tissues or 
push the gingivae away from the surfaces of the teeth. Too 
often people blindly and violently thrust the toothpick be- 



160 HYGIENE: DENTAL AND GENERAL 

tween the teeth, in an attempt to relieve some slight irrita- 
tion, until actual bleeding of the gums is produced. Another 
vicious and unsightly habit is the prolonged use and chewing 
of the cheap wooden toothpick from which splinters are de- 
tached to irritate the membranes of the mouth and throat. 
The toothpick should be used privately, not publicly. 

Mouth Washes, Tooth Powders and Pastes. — Prinz states 
that the sterilization of the oral cavity by any antiseptic 
which can be employed with safety is impossible. This being 
the case, the use of commercial preparations advertised to do 
this is not only useless but may be harmful, and their use 
should be condemned. 

We have shown that the saliva possesses many of the de- 
sirable qualities of a mouth wash. The ideal mouth wash 
should be of a similar nature, with the addition of a bacteri- 
cidal property. The qualities of the mouth wash should be 
such that it will not irritate the soft tissues, that it will not 
destroy the salivary ferments, that it will be bactericidal, 
that it is not poisonous if swallowed. The wash should be 
readily available and inexpensive so that it may be used 
freely and without harm. The writer has for many years ad- 
vised the use of salt and water for this purpose. Prinz has 
shown that physiologic salt solution reduced the oral flora by 
50 per cent, and he advises the use of this solution with the 
addition of half an ounce of lime water to eight ounces of a 
salt solution. The lime water is mildly astringent and is a 
solvent of mucinous material. Fones advocates the use of 
lime water alone, and states that five cents worth of coarse 
unslaked, lime such as the masons use for coarse plaster will 
keep a family supplied with the best kind of mouth wash for 
a whole year. 

Tooth powders are largely used as an aid in mechanically 
cleansing the surfaces of the teeth. Much injury may result 
from the use of an abrasive material and only the finest pre- 
cipitated calcium carbonate should be used for this purpose. 
This may be combined with a small amount of soap and sac- 



ORAL PROPHYLAXIS l6l 

charine and flavored with, one of the essential oils. A suitable 
powder may be made by thoroughly mixing a half-pound of 
finest grade English precipitated chalk with three grains of 
finely powdered saccharine, a half-ounce of powdered castile 
soap and 50 to 100 drops of oil of wintergreen or peppermint. 

Pastes are made by adding gelatine or glycerine to the 
powder. 

Tooth Cleansing Foods.— The use of slightly acid fruit 
as the last article of food to be eaten in a meal is to be com- 
mended for its efficacy in the removal of sticky particles of 
food and its stimulating effect upon the salivary glands, 
thereby promoting a free flow of saliva which, quickly neutral- 
izes the acid. The lunch which the child carries to school 
should contain an apple or an orange for dessert instead of 
the jam, cookies and sweets so often used. 

Care of the Mouths of Children. — It is of the uttermost 
importance that the growing child should be taken to the 
dentist for frequent examination. Beginning at the age of 
three years a careful inspection should be made at least every 
three months. This inspection should include not only an ex- 
amination for cavities of decay, which should be immediately 
treated or filled, but also a study of the dental archea to de- 
termine whether normal development is taking place. Slight 
stimulation by properly directed but gentle force may be neces- 
sary to bring this about. If retarded development is dis- 
covered early, very little interference is necessary to stimulate 
growth but if neglected the consequences may be serious. The 
treatment of incipient caries by the dentist by the use of ni- 
trate of silver will frequently inhibit decay, and the necessity 
for filling the deciduous teeth may be avoided. 

Septic Teeth as a Source of Systemic Disease. — During 
the past five years much has been written on this subject and 
investigators of prominence both in medicine and dentistry 
have, after exhaustive research, arrived at conclusions so 
similar as to justify the statement that in a variable per- 
centage of persons suffering from lesions of the kidneys, heart 



162 HYGIENE: DENTAL AND GENERAL 

and joints, x-ray and bacterial examination will reveal the 
presence of septic foci around the roots of one or more teeth. 
The removal of these teeth is often followed by marked im- 
provement of the general symptoms. 

Kosenow (Journal of Dental Research, Vol. 8, No. 3, Sept., 
1919) states, that the number of persons suffering from dis- 
eases directly attributable to dental foci of infection as well as 
from nonrelated conditions which have been cured or bene- 
fited by elimination of foci of infection, in various branches 
of medicine, is so large as to be quite sufficient to prove the 
general truth of the idea of causal relationship. He advises 
the removal of all nonvital teeth in persons suffering from 
arthritis, heart or kidney affections, and some other forms of 
disease for which other causes cannot be found. It is easy 
to see the possibility of an infection spreading from the region 
of the mouth to other parts of the body; but we believe that 
the number of cases attributed to this cause is greatly over- 
estimated. Cases are on record showing an undoubted re- 
lationship between systemic infection and dental foci by the 
marked improvement produced by the elimination of the dis- 
eased teeth. But to act upon the hypothesis that diseased 
teeth represent the sole cause of these systemic diseases and 
to advise wholesale removal of useful organs, is entirely un- 
warranted. Certainly teeth should never be removed merely 
because no cause for systemic disease is apparent. This is 
a matter in which the dentist must take an independent stand 
and his knowledge of dental pathology should be sufficient to 
enable him to determine whether or not extractions should be 
made, whatever may have been the prescription of an attend- 
ing physician. There is no excuse for the indiscriminate ex- 
traction of useful teeth. 

Taking the opposite point of view from that of Cotton, 
Rosenow, Hartzell and others, Howe states that "a focus of 
infection is a localized pathological area in which bacteria 
are to be found. Here the process is centralized and if the 
forces of immunity are unimpaired, the bacteria if not actu- 



ORAL PROPHYLAXIS 163 

all}' destroyed are walled off from the rest of the human 
system, moreover, the individual attains a high and specific 
immunity against this specific morbid process. Bacteria are 
not discharged freely into the circulation to wander at will 
and to settle without rhyme or reason at any point they 
choose. Once they enter the blood they are easily disposed of 
by all the forces of immunity." 

While this statement seems a sane viewpoint, especially 
so when the comparative minuteness of the septic area in- 
volved in the chronic alveolar abscess is considered, yet the 
degree of acquired immunity to any given organism may be 
variable or even lost, and it is in the period of lowered re- 
sistence that the possibility of systemic infection is present. 

Were this not the fact, the danger of general septicemia 
from infective processes in any part of the body would be neg- 
ligible. That this is not the case is amply proven by clinical 
experience, and by the fact that the first surgical law in the 
treatment of any abscess is the establishment of drainage. 
That there is an element of danger in the presence of oral 
septic conditions would seem to be implied by Dr. Howe's 
statement that "all oral septic conditions should be cleared 
up." Better still would be the statement that septic oral 
conditions should be prevented. 

There is some evidence that certain types of insanity are 
produced by abnormal mouth conditions. It is perfectly rea- 
sonable to make a distinct connection between the disturbances 
of the mental equilibrium and a local condition where pres- 
sure upon the nerves is exerting a constant zone of irritation 
such as an impacted condition of the teeth. This is undoubt- 
edly shown in the nervous manifestations which occur during 
the period of dentition in childhood. It is much easier to con- 
ceive of neuroses being related to conditions of impaction than 
to understand how they can be related to conditions of infec- 
tion as some medical writers believe. Cotton says that "in 
about 25% of the cases of the functional types and dementia 
precoxia groups, foci of infection in the teeth alone are the 



164 HYGIENE: DENTAL AND GENERAL 

etiological factor, and extraction of the affected teeth is fol- 
lowed by complete recovery." Corroboration from many 
sources would seem necessary before accepting such a sweep- 
ing statement and one so far reaching in its effects. 

The fact that the loss of the vitality of the dental pulp 
through the inroads of caries and the infected organic matter 
contained in the tubuli of the dentin is the primary cause 
of a very large percentage of these foci at once suggests the 
possibility of the absolute prevention of these serious sys- 
temic conditions by hygienic measures. 

While it may not be possible to prevent the formation of 
cavities of decay in the teeth which may eventually infect 
the dental pulp and lead to its death, yet careful regard of 
the principles of hygiene and the reinforcing of the protective 
agencies supplied by Nature, proper attention to diet and the 
exercise of the function of mastication will be effective to a 
surprising degree. 

In view of the possible far reaching effect of dental dis- 
ease it becomes the prime function of the dentist to instruct 
those coming under his care in such a way as to make clear 
the measures at hand for the prevention of dental caries. 



CHAPTER IX 

COMMUNICABLE DISEASES 

Three Great Plagues.— Diseases which are spread because 
of the existence of unsanitary conditions have been rapidly 
brought under control, but the diseases which are spread 
largely by personal contact have not been correspondingly re- 
duced.- Perhaps no illustration is better than the communi- 
cable disease history of the army during the four last wars. 
We may show graphically how the number of disease deaths 
have declined in relation to the number of battle deaths. 
This is a remarkable achievement but it is chiefly an achieve- 
ment of sanitation. Intestinal and insect borne fevers have 
been almost eliminated. On the other hand the respiratory 
disease rate remains very high. Pneumonia caused 13 per 
cent of the deaths of the Civil "War and but 3 per cent of the 
deaths in the Spanish War. But in the recent war it was a 
dread disease and caused 85 per cent of all deaths from dis- 
ease, having a death rate of over 9 per thousand. If the 
respiratory diseases had been eliminated from our army in 
the world war the army disease death rate would have been 
practically that of the civilian population. 

In civil life as well as in warfare the diseases transmitted 
by mouth and nose secretions present a great unsolved prob- 
lem. It is not our purpose to consider here the detailed path- 
ology or the administrative methods of control for the various 
communicable diseases. Appendix A contains a brief but 
comprehensive summary of the public health facts regarding 
them. There are however, three diseases or groups of diseases 
which are of paramount importance to society and which 
particularly interest the dental practitioner because they are 
communicable and because the infective organisms are found 

165 



166 



HYGIENE: DENTAL AND GENERAL 



in the oral cavity. We may refer to these diseases in popular 
language as the Great Red Plague, the Great White Plague 
and the Great Pandemic. They are syphilis, tuberculosis, and 
common cold. Progress can be made against these scourges 



disease: 



DISEASE 



BATTLE 



BATTLE 



15 



33 



Mexican War 
1846-48 



Civil War 
(North) 
1861-65 



BATTLE 



DISEASE 



BATTLE 

m 

Spanish War 
1898 



DI SEASE 

I 



53 



PRESENT WAB 

to Nov 11 

1918 



Fig. 27. — Comparative figures showing the number ot disease and battle 
deaths each year per thousand troops in the wars of the United States. (United 
States Army figures.) 



only by a broad and almost universal knowledge of their 
nature, their seriousness, transmission and the methods by 
which they may be combated. 



COMMUNICABLE DISEASES 



167 



TUBERCULOSIS 

Prevalence. — Descriptions of tuberculosis may be found 
in the earliest medical writings. It has always been an impor- 
tant disease. It is the most wide spread of all infections and 
correspondingly the greatest single cause of the death. At 
least 9 per cent of all deaths are due to this disease. Ten 



MEA5LE5 

SCARLET FEVER 

ORGANIC HEART DISEA5EV4% 

APPENDICITIS ~A% 

PERITONITIS -5 

TYPHOID .5-/o 

BRIGHT^ DISEASE .5% 

5EPTCEMIA 6%n 

EMPVTMIA 11% * 




Fig. 28. — The relative proportion of army deaths caused by the principal diseases 
in the war with Germany. (United States Army figures.) 



million of the people now living in this country will die of 
tuberculosis and yet it is a preventable disease ; we know its 
cause and we know how it may be prevented. It is most un- 
fortunate that tuberculosis is a disease of young people and 
carries away its victims in the prime of life at the height of 
their earning and productive capacity. 



168 hygiene: dental and general 

It has been estimated that the number of cases of tuber- 
culosis in any community is approximately 10 times the num- 
ber of annual deaths from the disease. That is, if a town has 
50 deaths from tuberculosis in 1920 it probably has 500 active 
cases. This figure has been confirmed by the recent tuber- 
culosis experiments conducted by the Metropolitan Life Insur- 
ance Company in the city of Framingham, Massachusetts. 
When this work was started there were three known cases of 
tuberculosis per annual death in the city. Large blocks of the 
population including thousands of people have received physi- 
cal examinations during this health experiment and a tuber- 
culosis expert has been provided who gives free consultation 
to the practicing physicians. The present figures show 9 cases 
of active tuberculosis and 11 cases of arrested tuberculosis per 
annual death. 

The Difficulties. — Why is it that the Great White Plague 
continues to take its annual toll in lives of our people while 
typhoid is being rapidly banished from our country? The 
following are some of the difficulties in combating tubercu- 
losis : 

(1) The disease is transmitted by contact and therefore has 
not the same direct relation to sanitation as does typhoid 
fever. 

(2) There is no way of producing an artificial immunity 
by the use of vaccine, and there is no satisfactory method 
of serum treatment. The reaction of the body to tuberculosis 
is cellular and not antitoxic. Instead of producing a chemical 
substance to combat the organism the body walls off the tu- 
bercle bacilli by the white blood cells and encapsulates them 
by the cells of the connective tissues. To be sure, the body 
becomes sensitized or anaphylactic from the first infection so 
that it may react more promptly, but since the reaction de- 
pends upon cell activity the bodily resistance depends upon 
the vitality of the individual and not upon a chemical sub- 
stance. 



COMMUNICABLE DISEASES 169 

(3) Bodily vigor which makes it possible to resist tuber- 
cular infection is impossible of universal attainment. It is 
very simple to say that fresh air, nourishing food, and suf- 
ficient sleep, will prevent or cure incipient tuberculosis but 
these very simple things are just what many people are un- 
able to secure. Under the economic basis of society it is not 
possible for everyone to have healthy work, sufficient recre- 
ation in the open air, and a suitable diet. 

(4) The disease is so benign and its onset so gradual that 
society is not aroused against it. A tuberculosis patient is 
often cheerful up to the very day of his death and there is 
nothing startling or terrible about the first stages of the dis- 
ease. If tuberculosis were accompanied by a high fever and 
a disagreeable rash as is smallpox, then rapid progress would 
be made in its elimination but as it is, we somehow conclude 
that because it is common it is not dangerous in spite of the 
fact that 1 out of 12 of our acquaintances will probably die 
with this preventable disease. 

Transmission of Tuberculosis. — It is to be remembered 
that there are two strains of organisms which produce this 
disease, the human and the bovine, and that there are many 
types of the disease, although phthisis or tuberculosis of the 
lungs is the most common form. Many other parts of the 
body are attacked including the bones, the meninges and the 
glands. 

Glandular infections among children are very common and 
a large percentage of such infections are with the bovine 
strain. It has been stated that from one-fourth to one-third 
of the tuberculosis in children under five years of age is 
caused by the bovine type of bacillus which is probably in- 
gested with cow 's milk. Recent hospital records show the bo- 
vine bacillus to be the cause of 80 per cent of the glandular 
cases in children under 4 years of age and the cause in 100 
per cent of such cases in children under one year of age. 
Records from a large number of cervical gland operations in 
children show that 65 per cent of gland infections were tuber- 



170 hygiene: dental and general 

culous and in 90 per cent of these the organism was the bovine 
type. Infection is therefore possible both from man and from 
animals and may be acquired both by inhalation and inges- 
tion. 

The chief source of infection from man is the sputum and 
it was formerly thought that the organism was most commonly 
acquired by being breathed into the lungs in droplets sprayed 
into the air by the cough of the tuberculous patient or in the 
form of dust. This type of infection does take place. Cornet 
was able to infect 47 out of 48 guinea pigs exposed to the dust 
produced by sweeping a carpet which had been purposely in- 
fected with tuberculous sputum but this was an unusual con- 
dition and the dose of the infection was great, Moreover the 
continual breathing of dust irritates the lungs and makes it 
easier for the bacillus to gain a foothold. But although in- 
fection by inhalation does occur we have probably overesti- 
mated the importance of this method in the past. 

We have recently come to regard more seriously the prob- 
ability of infection through ingestion. The opportunities for 
infection in this manner are countless and it has been shown 
that the organism may make its way from the throat and 
tonsils to the glands of the neck and from the small intestines 
to the abdominal glands, to the lungs and other parts of the 
body. No doubt the presence of decayed teeth and infected 
tonsils makes it easier for the bacilli to multiply in the body 
by providing acceptable lodgings in the mouth and throat and 
by reducing bodily resistance. 

We must accordingly recognize the danger of tuberculosis 
infections from contact in any of the various ways by which 
the infectious material from a tuberculous patient may reach 
our mouths. It may be that we handle infected material and 
then carry the fingers to the mouth or it may be that the in- 
fection is carried by milk, flies, cups, handkerchiefs, or other 
articles. This danger should make us more careful of food 
sanitation. 



COMMUNICABLE DISEASES 171 

The number of bacteria taken into the body is important 
as it has been shown that men and experimental animals can 
resist a limited amount of infection. In fact investigators 
assert that almost every individual who has lived to the age 
of 25 or 30 years will show tubercular lesions at autopsy, al- 
though they may never have developed clinical symptoms of 
the disease. It seems therefore that everyone must receive 
tubercle bacilli. The question of whether we have tubercu- 
losis or not depends upon the size of the dose and our degree 
of natural immunity, which in this case is directly related to 
general health. 

Tuberculosis is not hereditary although it is possible that 
some predisposition to it may be inherited. Of course if the 
child is taken care of by a tuberculous mother there is great 
opportunity for early infection. 

The disease may indeed be spread through contaminated 
water supplies. Sputum which has not been disinfected fre- 
quently finds its way into the sewer and the feces themselves 
contain tubercle bacilli. These organisms are enclosed in a 
little fatty sheath and are therefore more resistant to cold 
water than many other organisms and it seems reasonable to 
believe that they may be present in a polluted water supply, 
especially since the vital statistics of various cities have shown 
a reduced amount of tuberculosis when the water supplies 
were improved. 

Prevention and Control. — We have in our hands many 
weapons for combating the disease which we are not always 
using to the best advantage. Some of these may here be de- 
scribed. 

1. Education. — In order that our campaign may succeed the 
people must understand the facts and the seriousness of the 
disease Fortunately the message is a hopeful one because 
tuberculosis is curable. The public should know this but it 
should also know that it is transmissible. Many infections 
could be avoided by better personal prophylaxis if people 
would insist upon good ventilation, refuse to use common 



172 HYGIENE: DENTAL AND GENERAL 

drinking cups or unpasteurized milk from cattle which are not 
tuberculine tested and if they would avoid intimate associa- 
tions with cases of tuberculosis. Much could be done also by 
securing a desire for wholesome diet and by removing mechan- 
ical obstructions to breathing and other predisposing factors. 

2. Segregation. — Much can be gained by separating the tu- 
berculous patient from uninfected individuals. Hospitals 
should be provided for the advanced cases and sanatoria 
should be available for the incipient cases. There is a prac- 
tical difficulty here, for hospitals and sanatoria are expensive 
and it is not always possible to persuade the individual most 
needing the treatment to accept it. We have been particu- 
larly lacking in sanatoria where the middle classes of society 
could receive treatment at a reasonably low cost. The legal 
power to forcibly remove, isolate, restrain and keep under 
treatment the irresponsible and incorrigible consumptive is 
needed for the welfare of the community. 

3. Home Treatment. — Even if enough sanatoria could be 
provided there are often disadvantages in removing a patient 
from his home and it is fortunate that so much can be done 
by home treatment if it is properly carried out. Dispensaries 
should be provided in every community for the diagnosis, 
treatment and instruction of the consumptive. If this phase 
of the work is properly conducted any case may receive 
prompt and early diagnosis and may be taught how to avoid 
infecting other people. Something may be done to secure 
better housing conditions, a more suitable type of work and an 
improvement of diet. If the patient will honestly, intelli- 
gently, and conscientiously obey instructions he may have 
every hope of improving his condition in his own home, pro- 
vided the disease is not too far advanced, and he will probably 
do better in mind and body if his home is not broken up. If 
the patient is unintelligent or incorrigible there is little hope 
for his recovery under any consideration and society must 
safeguard the health of the people who would be brought in 
contact with him and endangered by his carelessness. 



COMMUNICABLE DISEASES 



173 



4. Tuberculosis Societies. — The National, State and Local 
Societies for the Prevention of Tuberculosis are important 
factors in combating the spread of the disease. What is every- 
body 's business is nobody's business and it is altogether too 
easy for the governmental agencies to neglect obviously needed 
activities for safeguarding the health of its citizens. Often 
the health official would like to do more but careless and un- 




Fig. 29. — An inexpensive and easily constructed outdoor sleeping porch. 

informed public sentiment will not support him. Fortunate 
is the community which has a group of interested citizens or 
an individual who can organize the necessary campaign for 
disease control. Successful campaigns of this type usually 
involve certain definite steps. The press, the physicians, the 
politicians, the Chamber of Commerce, the business interests 
of various groups must first be aroused and interested ; then 
a local committee is formed and a tuberculosis exhibit is se- 



174 HYGIENE: DENTAL AND GENERAL 

cured from the National Society for the Prevention of Tuber- 
culosis or from the State Board of Health. A local tubercu- 
losis society is formed, a dispensary is established with a 
physician and nurse in charge and then a day camp may be 
provided. The municipal authorities are usually ready to 
take over the work at this point and carry it on with whatever 
additions and improvements may be necessary. 

SYPHILIS 

Venereal diseases present what some public health workers 
regard as our most important health problem and yet little 
was done in an official way for their scientfic prevention pre- 
vious to the last decade. In one of the three venereal diseases 
(syphilis) mouth lesions are very common and the dentist 
may have to work upon infected individuals. But we wish 
the dentist to appreciate the social as well as the professional 
aspects of the disease and we shall therefore treat both phases 
of the question. 

Importance. — Syphilis did not appear in the civilized 
world until 1493. There is evidence (Journal American Med- 
ical Association, June 12, 1915, Vol. LXIV, 24, p. 1962) that 
it was carried to Europe by the crew of Columbus on the re- 
turn of his first voyage. By those members of the crew who 
joined the army of Charles VIII of France it was carried in- 
to Italy with the invasion of that country for the conquest 
of Naples in 1494. The epidemic which began there rapidly 
spread over all Europe with the most serious consequences, 
for the disease was then new and its course was extremely 
rapid and severe. 

The seriousness of this disease has not been realized because 
its existence has been hidden. Until recently the only accu- 
rate data which we have had regarding the presence of the 
disease were secured from military organizations. It has been 
easy to conceal the presence of the disease in civil life because 
the infected individual is not physically incapacitated during 



COMMUNICABLE DISEASES 175 

its early stages. Kober (Transactions Association American 
Physicians, Philadelphia, 1911, Vol. XXVI, p. 155) gives a 
table showing the prevalence of the disease in certain military 
groups for specific years. 

Differentiated Infections Per Thousand Men 

Year Syphilis Chancroid Gonorrhea Total 

U. S. Army 1909 30.45 30.77 135.77 196.99 

U. S. Navy 1909 26.49 28.23 105.11 159.83 

Japanese Navv 1907 139.75 

British Navy." 1908 37.46 17.87 67.16 122.49 

British Army 1908 35.1 28.23 40.7 75.8 

Japanese Army 1907 10.1 10.4 17.1 37.6 

Prussian Army 1907 4.4 2.1 12.2 18.7 

The variations of this table as well as more recent figures 
from our own army indicate that much may be done to limit 
the amount of infection. The following figures are taken from 
a statement of Colonel P. M. Ashburn, contained in Report 
of Hearings (H. R. 5123) Excluding Advertising of Cures for 
Venereal Diseases from the Mails. 

Army Venereal Incidence Bate per 1,000 for Preceding Years 

year rate year rate 

1911 163.49 1914 110.69 

1912 136.70 1915 107.71 

1913 99.22 1916 103.35 

1917 113.82 

Incidence in Camps during War per 1,000 60 

Incidence in A. E. F. during War per 1,000 45 

We have recently learned more about the venereal diseases 
in civilian as well as military life. That venereal disease con- 
trol is a civilian as well as a military problem is shown by Dr. 
W. A. Sawyer, Major M.C. /U.S.A. (American Journal of Pub- 
lic Health, May, 1919) who states the result of special reports 
rendered by Camps Upton, Dix, Meade, Lee and Pike for a 
period of 24 weeks from March 29, 1918 to November 15, 1918. 
Taking these five camps together the annual venereal disease 
rate for the entire period was 347.88 per thousand men. The 
rate for cases contracted in civil life and recorded as of the 



176 HYGIENE: DENTAL AND GENERAL 

date when first discovered was 336.96, while the rate for cases 
contracted after enlistment was only 10.92. Less than % 
of the 4.2,032 cases in these camps were contracted after en- 
listment. Major Sawyer believes that for all the troops in 
this country including the organizations that had been longer 
in the service than the newly drafted men mentioned above 
five to one was a close estimate of the ratio between the cases 
contracted before enlistment and those contracted afterwards. 

In spite of prompt isolation, thorough and proper medical 
treatment, the compulsory use of prophylactic stations, the 
elimination of prostitution so far as possible in the region of 
camps and a thorough educational program, there was a loss 
to the army representing 2,195,000 days of service between 
April 1917 and September 1918 {United States Public Health 
Service Reports, Oct. 24, 1919) . However, even in the absence 
of specific records we may be certain that this is a relatively 
slight time loss compared with that of previous wars. 

Some idea of the more serious effects of syphilis are found 
in a study of Mattauschek (Medicinische Kiinik, 1913, Vol. 
IX, p. 1544) who investigated 4,134 cases of the disease occur- 
ring among officers of the Austrian Army between 1880 and 
1900. Of these officers 14.64 per cent were dead or disabled 
as a result of the disease. Of this group 20 had died, 198 had 
severe paresis, 113 had locomotor ataxia and 132 had cerebro- 
spinal syphilis, 80 of whom- were insane. 

But these figures do not tell the whole story because the 
disease although hidden from the public greatly reduces the 
vitality of its victims and an early death is likely to occur 
from a variety of other causes. Very few of the insurance 
companies will accept syphilitics as risks and even those com- 
panies which accept cases after thorough treatment usually 
refuse to carry the individual after 55 years of age. 

The effects of this disease upon the offspring are perhaps 
more serious than the effects upon the diseased parents. The 
active disease may be inherited from either the father or the 
mother ; or serious defects may be transmitted to the offspring 



COMMUNICABLE DISEASES 177 

because of the presence of the disease poison. These more 
frequently manifest themselves in serious abnormalities of the 
nervous system. 

Nature of the Disease. — When an infection is produced 
by Treponema pallidum there first occurs a hard indurated 
ulcer or chancre in the skin or mucous membrane at the site 
of the initial infection. But the spirochetes soon invade the 
whole system and the second stage of the disease is marked 
by fever, anemia, the involvement of lymph nodes, and erup- 
tions upon the skin and mucuous membranes. The mucous 
patches in the mouth appear at this time and the disease is 
highly infectious. During the third stage of the disease local- 
ized granulomatous growths (gummata) appear in the various 
organs of the body and it is following this stage that the 
serious effects upon the central nervous system are produced. 

Transmission. — The spirochete of syphilis has been shown 
(Zinser and Hopkins: Journal American Medical Association, 
Vol. LXII, p. 23, June 6, 1914) to persist on a moist towel 
for IIV2 hours. It does not resist dryness and will not grow 
after having been dried on a slide for one hour. It is a rela- 
tively frail organism but of such viability as to be transmitted 
in other ways than through sexual approach. In fact ac- 
cidental infections, contracted outside of venery, are more 
common than is ordinarily supposed. Even a slight scratch in 
the skin is sufficient to permit the introduction of the virus 
as has often been demonstrated by infections upon the hands 
of surgeons and in the practice of midwifery. It is possible 
for the disease to be transmitted by kissing, or by the use of 
common drinking cups or common towels. Dental instru- 
ments, the barber's razor, pipes, spoons, or glasses, may con- 
vey the infection if proper precautions are not used. This 
possibility for innocent infection makes the disease a menace 
to every member of the community because syphilis is present 
in every class of the social scale. 

Immunity. — There is an immunity conferred upon a non- 
syphilitic fetus by the syphilitic mother and an immunity 



178 HYGIENE: DENTAL AND GENERAL 

conferred upon the nonsyphilitic mother by the syphilitic 
fetus. The first condition was long ago set forth by Prof eta's 
Law which holds that a healthy child will not contract syph- 
ilis from nursing a syphilitic mother. The other principle 
is known as Baume's or Colles' Law which asserts that a syph- 
ilitic child born of a healthy mother will infect the most 
healthy nurse but not its own mother. There is no natural 
immunity to syphilis. 

Prevention. — A study of the methods of control enumer- 
ated for this disease in Appendix A will show that we have 
recently made a good deal of progress in combating the mal- 
ady. The emergency of war allowed the inception of a gen- 
eral campaign against it. Now the people as well as the physi- 
cians and health officers realize that the venereal diseases must 
be treated like all other contagious diseases if they are to be 
eliminated. Consequently it has been possible to establish 
measures to secure the reporting of cases, and their continued 
treatment. Aided by the Chamberlain-Kahn Bill, which pro- 
vided conditionally for the distribution of $1,000,000 among 
the State Boards of Health each year for the two fiscal years 
beginning July 1, 1918 together with other appropriations for 
activities within the Bureau, the U. S. Public Health Service 
has conducted its campaign against venereal diseases by assist- 
ing in: 

1. Securing prompt reporting. 

2. Carrying on repressive measures. 

3. Establishing free clinics for treatment. 

4. Carrying on a general educational campaign. 

Forty-six states (all but Pennsylvania, Nevada and the 
District of Columbia) adopted the regulations necessary to 
obtain their quota of Federal money for the first year. This 
involved the establishment of a special Department or Di- 
vision of Venereal Diseases and the institution of proper con- 
trol regulations. It is to be hoped that this disease will in 



COMMUNICABLE DISEASES 179 

the future receive the attention it deserves from health author- 
ities and be handled like other communicable diseases. 

An idea of the treatment facilities furnished by the U. S. 
Public Health Service and the State Boards of Health may 
be obtained from the following summary of the July report 
{Public Health Report, September 5, 1919). During this 
period .131 clinics were operated and for the month 5,624 new 
cases of venereal diseases were admitted making a total of 16,- 
871 under treatment. A total of 61,578 treatments were ad- 
ministered to patients and 10,952 of these individual treat- 
ments were the administration of arsphenamine. There were 
discharged as cured, 314, as non-infectious but not cured, 244, 
as probably cured, 893. Altogether during the 10 months — 
October 1918 to July 1919— over 230,000 cases were treated at 
the 267 United States Public Health Service and State Clinics 
which reported. Many other cases were treated but not re- 
ported. 

Educational Program. — Perhaps the educational work 
carried on during the war was the most important part of the 
campaign because after all the continuation of suitable ad- 
ministrative measures depends upon the support of the com- 
munity. We have already indicated in our discussion of sex 
hygiene that the young man or the young woman should be 
told of the danger of venereal diseases at the right time and in 
the right way. This can now be more easily done than in the 
past. The Public Health Service and State Departments of 
Health have prepared special and admirable pamphlets for 
different groups and ages. During the war the motion picture 
"Fit to Fight" prepared specially for men in the service was 
shown to practically every man in the army and navy. Since 
then this picture and others like "The End of the Road" 
have been shown to a large percentage of our civil population. 
These films have been well made and if shown under the right 
auspices they are useful and instructing to young men and 
women. They can best be shown under the supervision of 
the State or Federal Government, in which case the picture 



180 



HYGIENE: DENTAL AND GENERAL 



may be preceded by a talk from a physician or health officer 
to make certain that the audience approaches the subject in 
the right frame of -mind. It is doubtful whether such films 
should ever be shown without being under the supervision of 
some medical or health officer. It is not proposed to use these 
pictures for boys or girls under 16 years of age. 

The public should learn from these sources that syphilis is 
a communicable disease, that its presence can be determined 
by clinical examination or by the Wassermann laboratory test 
upon the blood serum. The disease is now curable by the use 
of salvarsan and allied products but the course of treatment 
must extend over three years and must be followed out 
honestly and completely. The best doctors insist that the 
marriage of syphilitics should never be sanctioned unless they 
have undergone three years of thorough treatment and have 
subsequently been without symptoms for at least one year. 
Prophylaxis with calomel ointment within 20 hours after ex- 
posure is a fairly successful but not a certain preventive 
against the disease. 

We may hope that the serious consideration which has been 
given this disease in the United States during the past few 
years will give health authorities a keener appreciation of the 
seriousness of the problem, that it will make the medical and 
allied professions more aware of their responsibility in warn- 
ing the patient against the spread of the disease and in keep- 
ing him under treatment until the disease is cured, and that 
the general public will understand the facts regarding the 
disease and insist that the practical and common sense medical 
and legal measures shall be taken for its control. 

COMMON COLD 

It may seem strange that the common cold should be listed 
here as the third great health problem but a moment's con- 
sideration will show that it is the most widespread of the com- 
municable diseases. It is continuously pandemic. Always 



COMMUNICABLE DISEASES 181 

and everywhere the common cold is present to a limited ex- 
tent and certainly no contagions disease enters the dentist's 
office so often as this one. We pay little attention to the dis- 
ease becanse it is not fatal and there are no good figures to 
show us what a tremendous loss it really produces. 

Let us consider merely the economic loss from this disease. 
Is it not safe to assume that the average workman loses two 
days a year from a cold? If this is true then thirty million 
people who are employed in industry lose a total of sixty mil- 
lion days work. If you reckon the average wage as $4.00 a 
day here is nearly a quarter of a billion dollars lost in wages 
alone. Add to that the cost of decreased production and the 
loss from throwing out of employment other people in the 
same department or depending upon the work of the absentee 
and the loss becomes truly appalling. And this does not take 
into consideration the loss of efficiency during the days when 
the individual works with a cold or the general impairment of 
health which colds produce; and the figures are for factory 
workers only. 

Are we justified in saying that common cold is not a serious 
disease merely because it does not produce death? The com- 
mon cold is an acute infection of the nose, pharynx, tonsils, 
larynx, trachea or upper bronchi ; and how often do neuritis, 
rheumatic fever, pneumonia and rapidly progressing organic 
diseases follow these conditions! 

The Cause of Colds. — The cold is an infection and not 
merely a congestion. It is contagious and runs through a 
family or through a school or through a group of workers 
just as any other infectious disease. It has not, however, a 
single cause. There are a variety of bacteria associated with 
catarrhal infections such as staphylococci, streptococci, pneu- 
mococci, the influenza bacillus, the diphtheroid bacillus and 
the bacillus catarrhalis. Many of these bacteria are normal 
inhabitants of the mouth and nasal passages and they are 
doubtless waiting for an opportunity to set up the disease 
anew when the vitality of the individual is lowered. 



182 HYGIENE: DENTAL AND GENERAL 

Catching Cold. — Many people still have the mistaken be- 
lief that drafts produce colds. Of themselves drafts cannot 
produce infections and a chill is not the time when the in- 
fection takes place but rather indicates the period when the 
cold is becoming more active. When a cool wind reaches the 
skin of a normal individual his vasomotor system reacts by 
removing the blood from the skin and thereby lessening the 
heat lost and the body further reacts by increasing the heat 
production. Removing the blood from the skin about the 
face, shoulders and back of the head will congest the blood 
vessels at the interior. This may increase the watery or serous 
exudate upon the inner surfaces of the throat and nasal pas- 
sages, and bacteria, which may be present normally or which 
have been recently acquired, find an opportunity to develop 
rapidly on these congested surfaces. Furthermore if the cool- 
ing effect is long continued the temperature of the body is 
reduced and in this way the resistance is lessened. If the 
vasomotor system of the body is in poor condition bodily ad- 
justments to changes in temperature are less efficient and 
drafts are more likely to produce injurious effects. It is by 
improving the vasomotor system that cold baths, physical 
exercise and vigorous health assist in keeping a person free 
from common cold. 

Conditions which cause a continual irritation in the nose 
and throat also predispose to colds. Chronic catarrh, en- 
larged tonsils, polypus, deviation of septum and adenoids are 
examples. No doubt a dirty mouth is more likely to harbor 
the bacteria which may produce common cold than a clean 
mouth. The quality of the air passing over the respiratory 
passages is also important. Poor ventilation which allows the 
air to become too dry or dusty will set up undesirable nose 
and throat irritation. The air should be fresh and of suitable 
temperature. If the home or work place is too warm the sud- 
den change of going out into the open will congest the breath- 
ing passages. It has been pointed out that in the coldest 
weather it is the passengers in the stuffy carriages of the train 



COMMUNICABLE DISEASES 183 

who catch cold and not the fireman and engineer. Arctic 
explorers have been free from colds while in the far north 
only to become reinfected by a return to temperate climate 
where reinfection took place. 

Since the organisms which produce cold are almost con- 
stantly in the month and nose the opportunities for infection 
are innumerable. Dr. Chapin has stirred the imagination by 
asking us to consider what would be the result if the secre- 
tions from the mouth and nose were of a bright color. If 
each individual shed from these cavities a different shade of 
an intense red dye it would be appalling to see how quickly 
the surroundings would take on a rosy hue. The fingers are 
constantly going to the mouth and nose and would quickly 
become a deep red color. The handkerchief would become 
quickly dyed, we would exchange material with the people 
with whom we shake hands and the door-knobs, trolley car- 
straps, our desks, books, and instruments would all acquire 
the color far too rapidly. Perhaps it would be fortunate if 
this could happen to us for a day. We would certainly have 
a revelation as to the amount of care which we should use in 
preparing and serving our food, and we might wish to abolish 
the habit of hand shaking. 

There are three important rules for the prevention and 
treatment of colds: 

(1) Remember that colds are spread by organisms in the 
secretions of the nose and throat, and try to avoid infection. 
We should be much more careful in avoiding contact with 
persons who have colds. We should not let people cough or 
sneeze in our faces and we should avoid using common eating 
or drinking utensils. We must educate or train ourselves in 
habits of sanitation or cleanliness as those words are inter- 
preted under the germ theory of disease. 

(2) Avoid predisposing causes. Drafts, poor food, extreme 
fatigue, lack of sleep, and bodily defects lower the resistance 
of a person so that colds may be acquired more readily. Do 



184 HYGIENE: DENTAL AND GENERAL 

not neglect the duty to yourself of keeping in good physical 
condition. 

(3) When you feel a cold coming on go to bed. This may 
seem a severe remedy but there are many reasons for doing it. 
Colds are most contagious during the early period and if a 
person isolates himself in bed he is preventing contagion as 
well as taking the best possible care of himself. The recon- 
structive forces of the body work best when a person is resting 
quietly in bed under proper conditions of temperature and 
nutrition. The body is rested and strengthened and the dan- 
ger of increasing the severity of the disease by exposure to 
cold, damp and fatigue is eliminated. To stay in bed for a 
day or two when a cold is first coming on is perhaps the best 
economy of time as well as a "safety first" procedure. 

INFLUENZA 

In 1890 the United States had a severe epidemic of la grippe 
or influenza. There were milder recurring epidemics during 
the next three years and since that time (prior to 1918) we 
have thought of influenza as a mild endemic disease. There 
was a fatality rate of about one death in a thousand cases. 
We have found the influenza bacillus in what seemed like com- 
mon colds, and we have spoken of the "grippe," "grippy 
colds ' ' and ' ' bad colds ' ' rather indiscriminately. 

In 1918 there began an epidemic of influenza which proved 
to be the most serious epidemic in the history of the world. 
The first cases of the great epidemic in America were brought 
to Boston on an army transport late in the month of August 
and from this city the disease rapidly spread to all parts of 
the country. During the winter of 1918 and 1919 there were 
nearly a half million deaths in the United States attributable 
to this disease. The influenza was frequently complicated 
with pneumonia and it was in this complication that the death 
rate was highest. Instead of losing one out of every thousand 
persons who had the disease during this epidemic we lost about 



COMMUNICABLE DISEASES 185 

five persons for every thousand people of our whole popula- 
tion. It is reported that in India there were five million 
deaths. 

Cause. — It was particularly difficult to combat because 
we did not and we still do not know the cause. The influ- 
enza bacillus was found in a large percentage of the cases but 
it seemed to many that there must be some other microor- 
ganism present. If the disease was due to the influenza ba- 
cillus alone the germ possessed a virulence of incomparably 
greater strength than that of the organism which has been 
present in the endemic form of the disease. Endemic influ- 
enza has presented much the same problem as do common 
colds. Epidemic influenza has presented an entirely new 
group of problems. It may be well to summarize some of the 
facts which have been brought to light from our recent sad 
experience. 

Morbidity and Mortality Rates. — Classifying the 45 cities 
of the Weekly Health Index into three broad geographical 
groups the Census Bureau found a variation in the mortality 
{Weekly Health Index, March 1, 1917). In the cities east of 
the Appalachians the mortality from pneumonia and influ- 
enza from September 14, 1918, to March 1, 1919, was approx- 
imately 5.6 per thousand ; in cities between the Rocky Moun- 
tains and the Appalachians 4.35 per thousand; and in those 
of the Pacific Coast 5.55 per thousand. There were, however, 
wide differences among individual cities. 

To gather further statistics house to house surveys were 
made by the Public Health Service from the following popula- 
tion groups; New London, Conn., 7,993; Baltimore, Md., 33,- 
361 ; certain smaller towns and rural districts in Maryland, 
12,669; Spartanburg, S. C, 5,257; Louisville, Ky., 12,602; 
Little Rock, Ark., 9,920; San Antonio, Texas, 12,534; San 
Francisco, Cal., 18,682. 

The case incidence was highest in children from 5 to 14 
years old and progressively lower in each higher age group. 
The ratio of pneumonia cases to total population varied from 



186 HYGIENE: DENTAL AND GENERAL 

6.3 per thousand in Spartanburg, S. C, to 24.6 per thousand in 
the smaller towns of Maryland. The pneumonia rate showed 
little correlation with the influenza attack rate. The ratio of 
deaths to population varied from 1.9 per thousand in Spartan- 
burg to 6.8 in Maryland. The death rate was by no means 
parallel to the influenza attack rate but was closely correlated 
to the pneumonia attack rate. The fatality from pneumonia 
was uniformly about 30 per cent except in San Antonio, where 
it was only 18.5 per cent. The death rate was notably higher 
in children under one year old, in adults from 20 to 40, and 
in persons over 60 ; higher in males than in females and higher 
in the white than the colored population. 

Immunity. — Some investigators believe there is a con- 
siderable but not absolute immunity conferred by an attack of 
the disease. In Baltimore the first canvass was made prior to 
December 11 and a second canvass was made in January. 
Among 32,600 people, 724 cases were found to have occurred 
since the previous survey. Upon an investigation of cases the 
clinical diagnosis of influenza in both attacks was confirmed 
in only 26 cases, or 0.37 per cent of the total and even in these 
cases the diagnosis was necessarily uncertain. It will be seen, 
however, that there was a very brief period between these 
studies and the author believes that other figures will soon be 
available to indicate that no lasting immunity is conferred by 
an attack of the disease. 

Control. — An important investigation by Col. Lynch and 
Lieut. -Col. Cumming (American Journal of Public Healtli, 
Jan., 1919) indicates clearly that influenza may be spread by 
a contamination of eating utensils which are not properly 
boiled in washing. The investigators compared two groups 
of troops living under comparable conditions except that in 
the first group the mess kits were collected and properly 
washed in boiling water while in the second group there was 
individual mess kit washing in water which was necessarily 
below the boiling point. These two groups were about equal 
in size. In the group having collective tableware washing 



COMMUNICABLE DISEASES 187 

there were 33,452 men, among whom there occurred 1710 
cases or a period rate of 51.1 cases per thousand for the 14 
days under consideration. Among the second group of ap- 
proximately the same size, where there was individual mess 
kit washing, there were 8208 cases or a period rate of 252. 
It was shown that "80% of the infections among 66,000 
troops were due to unsanitary messing arrangements. ' ' Sub- 
sequent studies of over 18,000 hotel and restaurant employees 
showed that there were 85 per cent more cases among those 
who had eaten from hand washed dishes not disinfected by 
boiling water. This is clearly a suggestion for sanitary dish 
washing (immersion in boiling water) in the home as well as 
in public eating places. 

In discussing the administrative control of influenza, Dr. 
Allen Freeman (paper read at the American Public Health 
Association meeting in New Orleans, October 28, 1919) 
stresses the need of further investigation into the nature of 
influenza. He states that although there is every reason to 
believe the disease is caused by a virus lodging in the nose 
and mouth and spread from secretions of the nose and mouth 
indirectly or through droplet infection these beliefs are not 
proved by experiments. The paper holds that prompt iso- 
lation is important and that educational measures are most 
helpful. However, the prohibition of public gatherings and 
the use of masks are not to be regarded as very important 
means of prevention. Until we can be certain that we know 
the virus of this disease, vaccination is not sound practice. 
The procuring of adequate medical and nursing service and 
the proper care of pneumonia cases are important in reducing 
mortality. 



CHAPTER X 

PUBLIC HEALTH ADMINISTRATION 

The health of the individual is protected, first, by proper 
personal hygiene, and second, by the activities of organized 
government in disease prevention. We are here considering 
the health administration of the Federal, State and local 
governments. 

Public Health Authority. — The division of the responsibili- 
ties for administering public health among National, State, 
and Municipal governments is dependent upon the relation- 
ship which these bodies bear to each other under the Consti- 
tution of the United States and the various State constitutions. 
Ours is a Federal government and each State has supreme 
power in those questions which affect that State alone. In 
such matters it may, if it chooses, direct the individual com- 
munity and it may not be interfered with by the Federal 
Government. In considering the activities of the public 
health officials we shall first investigate their powers under 
the law and then discuss their activities. 

FEDERAL PUBLIC HEALTH FUNCTIONS 

The National Government has only such powers as are 
granted to it by the Constitution. In such matters State law 
must give way but where power is not specifically given to 
the National Government it is assumed that the power lies 
with the states. There is no specific mention of any power 
over the public health in our Federal Constitution but author- 
ity is granted "to make all laws necessary and proper for 
carrying into execution any of the powers placed by the Con- 
stitution in the Government of the United States or in any 

188 



PUBLIC HEALTH ADMINISTRATION 189 

department or officer thereof. ' ' And "power to regulate com- 
merce, levy and collect taxes and carry out treaty agree- 
ments" are specifically granted to the National Government. 
Certain public health activities are very properly carried on 
under these broad powers. 

The Power to Regulate Commerce. — The first general 
clause by which the Federal Government has power to regu- 
late public health is the clause giving it power to regulate 
commerce with foreign countries and among the several states. 
The words "commerce" and "regulate" are not defined and 
their meaning has been gradually enlarged. Commerce is in- 
terpreted to include not only the active transportation of 
persons and things from one place to another but also arti- 
ficial land and water routes, terminals, harbors, vehicles, and 
the persons, both carriers and shippers, consignees, employers 
and employed, who are engaged in the active transportation. 
Commerce embraces purchases and sales and the negotiations 
entered into in order to lead to sales. Indeed there is a tend- 
ency to regard manufacturing as a part of commerce where 
its regulation is necessary to the effective regulation of what 
is admittedly commerce. 

The power to regulate includes not only the right to charter 
companies and the right to regulate contracts between ship- 
pers and carriers, carriers and their employees, between sellers 
and purchasers, but also the right to prohibit commerce on 
certain articles, to prohibit certain methods of carrying on 
commerce and to license those engaged in commerce. 

The power of the government through this clause is the 
power to prohibit, under criminal penalty, the interstate trans- 
portation of persons or articles. It includes, therefore, the 
power of quarantine against persons or things to prevent their 
entrance from one state to another where such an entry may 
be judged to endanger the public safety. In commerce with 
foreign countries the government may take action in the 
nature of either an embargo or an inspection. 



190 HYGIENE: DENTAL AND GENERAL 

The power of the government to restrict the transportation 
of an article includes the power to determine whether the 
article transported falls within the prohibited class and thus 
provision is made requiring the labeling of articles and the 
inspection at the place of manufacture of articles intended 
for interstate transportation as well as for the licensing of 
persons engaged in their manufacture. 

An important use of this power was the enactment of the 
Food and Drug Law which forbids the transportation from 
one state to another of adulterated food products and drugs. 
The law was upheld by the Supreme Court as constitutional. 
On the other hand, the Child Labor Law which forbade the 
transportation of goods made in factories where children un- 
der 14 years of age were employed, or where there were em- 
ployed children under 16 years of age who worked more than 
eight hours a day was not upheld by the Supreme Court. It 
was declared unconstitutional because it was regarded as an 
attempt to regulate the methods of manufacture within a state. 
The transportation of articles manufactured by child labor 
could not in the nature of things be harmful and therefore the 
injury to health which resulted was done in the state of manu- 
facture and hence was due to manufacturing and not to 
commerce. 

Taxation. — The second source of power in regulating pub- 
lic health is the power to "lay and collect taxes, duties, im- 
posts, and excises to pay the debts and provide for the common 
defense and general welfare of the United States." The 
power to tax is in reality the power to destroy. Congress has 
in the taxing power a method of protecting public health 
which naturally lends itself to matters where prohibition 
rather than regulation is sought. The only limit to this power 
is the condition that the classification of articles and persons 
to be taxed must have some reasonable relation to the object 
sought. 

The last revenue bill provided a prohibitive tax on all man- 
ufacturers employing child labor. The litigation which is 



PUBLIC HEALTH ADMINISTRATION 191 

bound to occur upon this point will undoubtedly determine 
more definitely the limits of Federal power under the right of 
taxation. Another example of the taxing power in the in- 
terest of public health is the Harrison Act, which regulates 
the use of drugs by exercising the taxing power. 

Defense and Welfare Powers. — The power to "provide for 
the common defense and general welfare of the United States" 
is also important. Under this power the government has es- 
tablished a national Public Health Service authorized to assist 
state health authorities and cooperate with them. Thus, al- 
though the United States Government may not interfere with 
the sanitary work of the states it may have a far-reaching 
influence on state health administration through its power of 
appropriating money for health work. 

Treaty and War Powers. — Congress, no doubt, may exer- 
cise legislative power in carrying out the provisions of treaties. 
Such powers, in the past, however, have not been largely exer- 
cised and their limits are not definitely set. It should also be 
remembered that in the District of Columbia, territories and 
reservations the Federal Government has complete powers, and 
that in time of war its power to raise and support armies and 
to provide a navy carries with it the power to do whatever is 
necessary to protect the health of soldiers and sailors, even 
within state lines. 

The United States Public Health Service. — The most im- 
portant branch of the Federal Government in its relation to 
health is the Public Health Service. The following concise 
statement regarding its development and organization was 
supplied by the Chief of the Section of Public Health Edu- 
cation, Dr. Charles Bolduan, in a letter written December 6, 
1919: 

The Public Health Service dates back to the end of the Eighteenth 
Century when, in 1796, steps were taken for providing medical and 
surgical relief to merchant seamen. At first this was financed by a 
per capita tax collected from the seamen, the funds being handled by 
the collectors of customs in the various ports. Subsequently this was 



192 HYGIENE: DENTAL AND GENERAL 

changed into a tonnage tax, collected through the same channels. This 
explains why the marine hospital work (the precedent of the present 
TJ. S. Public Health Service) came to be lodged in the Treasury De- 
partment, for the collection of customs was naturally a branch of 
the Treasury Department's work. With the enormous growth of the 
American Merchant Marine in the first half of the Nineteenth Century 
this method of providing for the merchant marine was found to be 
inadequate and the government, therefore, established l( marine hos- 
pitals ' ' at various important points. 

In an effort to guard against the introduction of dangerous pestilen- 
tial diseases from without it was natural that the officers of the marine 
hospitals, stationed as they were at the important ports of entry, should 
come into close relation and take an active interest in maritime quar- 
antine matters. In addition to this, the repeated introduction of 
yellow fever into the southern states and the alarm occasioned thereby 
caused repeated calls to be addressed to the Federal Government to take 
charge of control measures at the infected points in order to prevent 
the spread of disease to other points of the United States. There be- 
ing no special Federal health agency, these calls were naturally re- 
ferred to the United States Marine Hospital Service. More and more, 
therefore, this Service began to undertake federal public health ac- 
tivities, a fact which was recognized by Congress when, in 1902, it 
changed the name of the Service to the United States Public Health Serv- 
ice and Marine Hospital Service. More recently still, in 1912, the name 
was still further changed to its present designation, namely the United 
States Public Health Service. 

The United States Public Health Service is a bureau in the Treasury 
Department. At its head is the Surgeon-General. He is assisted by a 
staff of Assistant Surgeon-Generals. Most of these have charge of im- 
portant functional divisions. As at present organized, the work is 
carried on under the following divisions : 

Division of Personnel and Accounts. (As its name implies, it has 
to do largely with matters of internal administration.) 

Division of Marine Hospitals. (In addition to caring for merchant 
seaman, this division has charge of all the medical and surgical relief 
work for discharged soldiers, sailors, marines and nurses who are bene- 
ficiaries under the War Eisk Insurance Act.) 

Division of Maritime Quarantine. (This conducts almost all the 
maritime quarantine stations for the United States and the insular 
possessions.) 

Division of Domestic Quarantine. (This controls the important field 
relating to the control of diseases through the interstate traffic.) 

Division of Scientific Research. (This is a large division engaged 



PUBLIC HEALTH ADMINISTRATION 193 

in studying the diseases of man through field investigations and labora- 
tory work.) 

Divisions of Sanitary Beports and Statistics. (This division collects 
information regarding the prevalence of communicable diseases, dis- 
seminates it through publications and otherwise to Health Officers and 
Sanitarians throughout the country.) 

Division of Venereal Diseases. (This recently created division was 
established by Congress primarily to safeguard the nation's manhood 
against the ravages of venereal infection.) 

Section of Public Health Education. (A recently established activ- 
ity for promoting public health through popular health education.) 

The personnel below the rank of the Assistant Surgeon- 
General consists of Senior Surgeons with a rating correspond- 
ing to that of Lieutenant-Colonel in the army, Passed Assist- 
ant Surgeons with the rating of Captains, Assistant Surgeons 
with the rating of 1st Lieutenants, Scientific Assistants with 
the rating of 2nd Lieutenants, Pharmacists, Orderlies, Tech- 
nicians, and other attendants with the rating of noncommis- 
sioned officers. These grades are largely for the convenience 
of these Federal officials in order to determine relative rank 
when sitting upon boards or commissions with army and navy 
officers. The Public Health Service is a civilian and not a 
military branch of government, although during the world 
war it was declared a branch of the military service by the 
President of the United States, being continued under its 
usual organization. 

The functions of the Public Health Service have been de- 
scribed by Assistant Surgeon-General McLaughlin as of four 
kinds. Police duties are first mentioned. These include the 
maintenance of quarantine and the prevention of the spread 
of disease from one state to another. The second activity is 
that of investigation. With increased appropriation from 
Congress the Hygienic Laboratory of the Public Health Serv- 
ice at Washington should be made a big center of research in 
preventive medicine, for it is obviously fitting that the Na- 
tional Government should undertake the solution of the 
nation's great disease problems. The third activity is that 



194 HYGIENE : DENTAL AND GENERAL 

of demonstration. With the cooperation of the state and local 
agencies, special pieces of work may be undertaken to prove 
the value of rural sanitation and other health measures. The 
fourth activity is that of the coordination of state and local 
activities in various parts of the country in order "to secure 
a synchronous attack upon any disease with uniformity of 
method over the entire area of the United States." For ex- 
ample in the national campaign against venereal diseases 
Congress appropriated one million dollars under the Chamber- 
lain-Kahn bill and under the cooperating agency of the Public 
Health Service the various states waged a uniform and suc- 
cessful campaign. 

The Public Health Service is the principal and most im- 
portant health agency of the Government. It has been ac- 
credited with all the powers that Congress can give it for 
doing health work. The nature of its activities is limited by 
the Constitution and the extent of its activities is limited by 
the failure of Congress to give it sufficient appropriations. 
Perhaps it is also handicapped by being a semimilitary organi- 
zation; because many people mistake the brown or blue uni- 
forms for those of the army or navy. The people regard 
health officials as "their servants" and object to the "red 
tape" and "army methods" of the Service which sometimes, 
perhaps of necessity, lacks the personal consideration and tact 
of local health organizations. 

Other Federal Health Agencies. — There are two other de- 
partments in the Federal Government which are doing rather 
extensive health work, the Children's Bureau in the Depart- 
ment of Labor and the Bureau of Education in the Depart- 
ment of the Interior. Many of the departments of the govern- 
ment are doing lesser amounts of health work and much is 
apparently being lost through lack of centralization and co- 
ordination. Attempts have already been made to secure a 
central health administration and this movement has doubt- 
less been strengthened by the recent organization of a Ministry 
of Health in both England and Canada. 



PUBLIC HEALTH ADMINISTRATION 195 

STATE HEALTH FUNCTIONS 

Under our form of government each state bears the respon- 
sibility for its health conditions and upon the state legislature, 
as the supreme power of the state, this responsibility prima- 
rily rests. The Federal Government has no right to interfere 
in those matters which affect only the state itself, but the 
towns and municipalities within the state are all bound to 
enforce the state law. The legislators, limited only by the 
constitution and responsible only to the electorate, are su- 
preme in their power to determine what health regulations 
shall be made and what official organization shall be provided 
by each municipality and by the state at large to ad- 
minister public health. Since public health administration 
within the state is directly dependent upon the law it may be 
profitable to consider the principles of health legislation at 
this point. 

Public Health Laws. — Public health laws may be divided 
into two groups; those statutory laws creating the public 
health organization, and those, statutory and otherwise, which 
govern public health administration. 

The first law providing for health organization was the 
Massachusetts law of 1797 establishing Boards of Health for 
towns and giving each board power to "make such regula- 
tions as it judges necessary for the public health and safety.' ' 
Since then the other states have made similar laws, the last 
enactment being that of Nevada in 1905, while many of the 
large cities have had special sanitary provisions incorporated 
in their charters. The type of local organization has varied 
in different states depending upon whether the administrative 
unit of government was the township or the county. The 
local authorities are required to keep the state authorities in- 
formed as to the sanitary conditions of their districts and in 
all cases local health ordinances must not contravene the laws 
of the state. Since 1855 each state has enacted a law creating 
a State Board of Health or its equivalent. 

In the legal side of public health administration, common 



196 HYGIENE: DENTAL AND GENERAL 

and constitutional as well as statutory laws are involved. The 
common law, or lex non scripta, consists of the court decisions 
made in the course of administering justice. The decision 
of a lower court or the opinion of an attorney has little value 
as a precedent, but the decision of the supreme court is bind- 
ing upon subordinate courts until overruled. Statutory laws 
are enacted by legislatures upon the basis of common law and 
their official interpretation has the force of additional legis- 
lation. 

Coincident with the growth of common law there is usually 
the establishment of institutions such as quarantine. These 
institutions, however, may become antiquated and abandoned 
as the quarantine of yellow fever. When conflicting with 
either statutory or constitutional law they are not lawful. 

All authority for the protective operations of government 
including the preservation of public health is derived from 
what is known as police power, an inherent function of govern- 
ment. In its exercise we find cases where there is sanction 
for otherwise illegal acts, such, for example, as the violation 
of personal or property rights to protect the safety of the 
people in great epidemics. 

The use of license is essentially police in nature. A license 
may be issued with a slight fee as in licensing milk dealers 
where it is the license rather than the fee which serves to re- 
strict or regulate the business. On the other hand, the issu- 
ance of licenses at a prohibitive cost has been a reasonable 
use of police power in restraining the liquor traffic. A tempo- 
rary license, or one which covers a single act, is ordinarily 
called a permit. 

Where a health officer is given power of discretion he may 
do any act within that discretion, and all that he does will 
be held to have been done with the express authorization of 
law. Should the health officer abuse his power of discretion 
he is amenable to prosecution, but the act to be criminal must 
be wilful and corrupt, and proof of this rests upon the com- 
plainant. If the officer has deviated from his legal authority 



PUBLIC HEALTH ADMINISTRATION 197 

through, a mistake in interpreting his power or a mistake of 
fact in applying the law he is liable as a private wrongdoer 
and responsible in such damages as may be proved. 

An officer is not subject to a private action for neglect of 
an exclusively public duty even to a person specially injured 
thereby, and in some cases even though the act were unlawful 
and malicious. If discretion be left entirely to the admini- 
strative officer, there is no way in which he can be forced to 
act. In the enforcement of statutory law, an officer is sub- 
ject to mandamus and also to probate action whenever he 
shall deviate from his prescribed limits of duty. 

Some laws like quarantine are mandatory as to action, but 
discretionary as to method. In court proceedings if the law 
be specific the only questions which may arise are those of 
fact; if discretionary, questions of fact, reasonableness and 
extent of discretion may be presented. 

A city's administration depends upon fixed rules. They 
are either written regulations or unwritten usages. "When a 
penalty is attached to a violation of the rules or regulations of 
the board of health, such rules must be published and due 
notice given before they can be made effective. Violations of 
the regulations may be punished by indictment, action being 
uniformly brought in the name of the town or city. 

Injunction is applicable to prevent executive action, the 
taking or impairment of property or the creation of nuisances. 
It is not used to direct or restrain the exercise of discretion- 
ary authority. 

A public health nuisance is a state of affairs which is dan- 
gerous to public health. Obviously a thing may be a nuisance 
under either common or statutory law. In a case of exigency 
the health authorities may summarily abate the nuisance, but 
if the owner of the property cannot get a formal trial before 
the abatement he is entitled to a hearing afterward. The 
burden is then upon the authorities to justify their action.* 



*For an extensive discussion of public health legislation see U. S. Public Health 
Bulletin No. CA published in August, 1912, "Organization, Powers and Duties of 
Health Authorities" ; also "Legal Principles of Public Health Administration, by 
Henry B. Hemenway. 



198 



HYGIENE: DENTAL AND GENERAL 



State Health Administration ; Organization. — Turning now 
to a consideration of state health administration we find that 
the oldest type of organization placed the administration of 
public health in the hands of a Secretary of the State Board 
of Health. He was the executive officer and his activities 
were guided by the policy and wishes of the Board. Eecently 
many states have changed their type of organization from a 
State Board of Health to a State Department of Health under 
the direction of a Commissioner with an Advisory Council. 
New York initiated this movement with its law of 1912. Mass- 
achusetts soon followed suit with a similar law, containing a 
few modifications and since then Maine, New Jersey, Connecti- 
cut, California, Ohio and several other states have adopted 
some form of the New York-Massachusetts plan. 

The organization of the State Department of Public Health, 
of Massachusetts, July 1, 1920, is as follows : 

"Working under the advice of the Public Health Council is 
the Commissioner of Health whose organization is made up 
of the following divisions: 



1. Sanitary Engineering 

Director and Chief Engr 1 

Asst. Engineers 12 

Draftsman 1 

Clerical .5 

Messenger 1 



Activities 

Advice to cities and towns in 
regard to Avatcr and sewage 
problems. 

Field surveys and investiga- 
tions necessitated thereby. 
Special Engineering projects 
imposed by the General Court. 



2. Water and Sewage 

Laboratories 

Director and Clif . Chemist ... 1 

Asst. Chemists ;. 5 

Biologist 1 

Laboratory Asst 1 

Clerical 2 

Lawrence Expt. Sta. 

Asst. Chemist 1 

Bacteriologist ■ 1 

Laboratory Asst 1 

Filter Attendant 1 

Laborer 1 

Activities 
Investigation of water, sew- 
age and trade waste problems. 



PUBLIC HEALTH ADMINISTRATION 



199 



3. Food and Drugs 

Director and Analyst 1 

Assistant Analysts 4 

Food and Drug Inspectors. . . .4 

Veterinary Inspectors 3 

Cold Storage Inspectors 2 

Clerical Inspectors 3 

Messenger 1 

Activities 
Examination of milk, food 
and drugs. Dairy Inspection. 
Cold Storage Inspection. 
Slaughtering Inspection. 
Food Economies. 
Drug Addictions. 
Patent Medicine Frauds. 
Arsphenamine Production. 



4. Administration 

Clerical 6 

Messengers 2- 



Activities 
Correspondence. 
Financial. 
Statistical. 
Eecords. 



5. Communicable Diseases 

Director 1 

Epidemiologist 1 

Dist. Health Officers 8 

Bacteriologist 1 

Asst. Bacteriologist 2 

Laboratory Asst 2 

Clerical 6 

Sub -division of Venereal 
Diseases 

Chief 1 

Epidemiologists 2 

Clerical 4 

Inspector 1 

Educationalist 1 

Subsidized Clinics 1G 

Activities 
Prevention of all Communi- 
cable Diseases, except tubercu- 
losis. 



6. Hygiene 

Director 1 

Asst. to Director 1 

Health Instructor 1 

Field Supervisor 1 

Clerical 2 

Dental Hygienist 1 

Instructor in Foods 1 

Sub -division of 
Public Health Nursing 

Chief 1 

Nurses 3 



Activities 
Infant Mortality. 
Child Hygiene. 
Industrial Hygiene. 
Eural Hygiene. 
Health Instruction. 



200 HYGIENE: DENTAL AND GENERAL 

7. Biologic Laboratories 8. Tuberculosis (Sanatoria) 

*Director 1 Director 1 

Asst. Directors 2 Clerical 4 

Expert Asst 1 Visitor .1 

Laboratory Assts 5 Superintendents 4 

Other Assts 3 Hospital Staffs ?? 

Technician 1 

Clerical 1 

Janitor 1 

Activities 

Manufacture and Distribu- 
tion of Diphtheria Antitoxin, 
Smallpox and Typhoid vaccines. 

Antimeningitis serum. Was- Activities 

sermann tests for Syphilis. Prevention of Tuberculosis 

*Part time. and Treatment in Sanatoria. 

The work to be done is practically the same no matter what 
the type of organization although naturally the extensiveness 
of the work done by each state varies with the size of its 
health appropriation, the efficiency and number of its person- 
nel and the extent to which the state supervises local health 
administration. We shall use the new type of organization 
in describing state health activities, because it is already be- 
coming the common type of organization and because it lends 
itself well to a description of health functions. 

The essential features of the New York State Department 
of Health are set forth in the law which created it. There 
are provisions for a Commissioner, a Public Health Council, a 
Sanitary Code, the employment of District Health Officers, 
and the creation of various Divisions. 

The Commissioner is appointed for a term of six years and 
must have had ten years experience in the practice of his 
profession and in public health duties. The Deputy Com- 
missioner is appointed and at pleasure removed by him. The 
duties of the Commissioner include a general supervision of 
the health activities of the State, the enforcement of public 
health laws and the sanitary code, the study of health con- 



PUBLIC HEALTH ADMINISTRATION 201 

ditions, and the keeping of vital statistics, while his powers 
include the right to modify a local ordinance and the right of 
entry which he may delegate to any of his employees. 

The Public Health Council- is composed of the Commissioner 
and six other members, three of whom are physicians, ap- 
pointed by the Governor for a term of six years and receiving 
a salary of $1000.00 per year over and above necessary travel- 
ling expenses. The Council has no executive or administra- 
tive duties but acts in an advisory capacity to the Commis- 
sioner and may at any time offer suggestions. 

The Sanitary Code, consisting of rules and regulations af- 
fecting the security of life or health, is enacted by the Public 
Health Council. The provisions of this Sanitary Code have 
the force and effect of law in all parts of the State and are 
only restricted in that they shall not discriminate against 
any licensed physician. These regulations are filed with the 
Secretary of State. In enforcement they supersede any local 
ordinances which may be inconsistent with them, and include 
besides sanitary regulations a statement of qualifications for 
Directors of Divisions, Sanitary Supervisors, Local Health 
Officers, and Public Health Nurses. 

It is to be noted that the legislature has delegated a limited 
amount of "hrw-making power" to the Public Health Council. 
In such a case the delegation of power is judicious and pro- 
gressive, for only a body of experts is qualified to work out 
the details of public health regulations. 

It is definitely provided that there shall be in the Depart- 
ment of Health nine Divisions, namely: 

1. Division of Administration. 

2. Division of Sanitary Engineering. 

3. Division of Laboratories and Research. 

4. Division of Communicable Diseases. 

5. Division of Vital Statistics. 

6. Division of Publicity and Education. 

7. Division of Child Hvgieix'. 



202 HYGIENE: DENTAL AND GENERAL 

8. Division of Public Health Nursing. 

9. Division of Tuberculosis. 

A division of Venereal Diseases has since been added. 

Sanitary Districts are formed by the Health Commissioner, 
and District Health Officers are appointed by him. It is their 
duty to keep in touch with local health officers, aiding them 
when necessary, to make special surveys, hold conferences, ad- 
just local questions of dispute, study mortality, promote the 
registration of births, inspect camps and Indian reservations, 
enlist physicians for emergency service, and assist in public 
education, and the enforcement of the sanitary code. 

Administrative Functions. — Let us consider briefly the 
activities of the various divisions of the State Department of 
Health. 

One of the first recognized duties of the state has been the 
collection of vital statistics. This includes the recording and 
analyzing of data concerning deaths, births, marriages, popu- 
lation, and diseases. The keeping of vital statistics is the 
bookkeeping of a state by which it keeps a record of changes 
in the population, which represents its great item of wealth. 
Just as an industrial concern keeps an account of its material 
assets and liabilities so the state must keep a record of its 
human assets and liabilities. It must know whether it is 
gaining or losing and where and how. If disease is to be pre- 
vented and lives are to be saved careful records must be kept 
to show where, when and how diseases and deaths are oc- 
curring: 

The recording and interpretation of vital statistics is a 
science in itself and highly trained vital statisticians are em- 
ployed for this work. The layman may not be particularly 
interested in the methods of interpreting statistics but he will 
at least wish to know what is meant by the most commonly 
computed rates. 

The hirtli rate is the number of births annually per thou- 
sand population. The crude death rate is the number of 



PUBLIC HEALTH ADMINISTRATION . 203 

deaths annually per thousand population. We also have what 
are termed specific death rates which state the number of 
deaths per thousand or per 100,000 population for specific 
diseases. For example a low typhoid death rate is 4.3 per 
100,000. 

Another important figure is the morbidity rate which is 
the number of cases of specific disease per thousand popula- 
tion (sometimes expressed as the number per 100,000 popu- 
lation). The fatality rate is the number of deaths from a 
specific disease per 100 cases (the per cent fatality). We 
say, for example, that among pneumonia cases the fatality 
rate was 33. 

By such figures our "life and death bookkeeping" shows 
us how we can tell just where our various communities stand 
in the matter of life-saving and health. When we realize that 
such figures show whether we live in a safe and healthy com- 
munity or a dangerous and sickly one, the statistics of our 
state and local health officers become most interesting reading. 
The registration of births, marriages and deaths is also im- 
portant for legal, social and property rights. 

The Division of Administration, which is presided over by 
the Health Commissioner, includes a supervision over the 
work of the district health officers, accounts, salaries, expendi- 
tures and other administrative details. 

An increasingly important division is that of Public Health 
Education. It embraces the publicity work of the State De- 
partment of Health, such as the circulation of the reports 
issued by the department, publicity work through the news- 
papers, the showing of health exhibits in various parts of the 
state, the issuing of pamphlets and instructive material to 
school children and to people generally, lectures, moving 
pictures and all of the numerous and valuable activities by 
which the state health department places before the people the 
important principles concerning the care of the health. 

The functions of the Division of Sanitary Engineering are 
to safeguard tHe water supplies and to insure proper waste 



204 HYGIENE: DENTAL AND GENERAL 

disposal throughout the state. Such a department maintains 
facilities for water and sewage analysis and is able to furnish 
the advice of an expert Sanitary Engineer in any problem of 
water supply and waste disposal. These problems will be con- 
sidered in a special chapter. 

The special duties of the Division of Communicable Diseases 
include activities in controlling and limiting the spread of 
various communicable diseases. An epidemiologist is usually 
attached to the Department, who promptly investigates in- 
cipient epidemics enabling the division to take more prompt 
and intelligent steps in restricting the disease. 

The Division of Child Hygiene maintains a personnel of 
trained workers in subjects of infant and child welfare, who 
make surveys, develop special state and local campaigns to 
improve the hygienic conditions of maternity, infancy and 
childhood and cooperate with private child-health agencies 
through the state. 

The Division of Public Health Nursing determines the 
qualifications of the public health nurse, employs a corps of 
nurses to assist district health officers and broadens the useful- 
ness of such nurses as are employed by various communities 
in the state through its assistance and cooperation. 

The Division of Laboratories and Research provides free 
laboratory diagnosis of communicable diseases, prepares and 
distributes vaccines and antitoxins to the medical profession 
and carries on public health research. 

The Division of Tuberculosis directs the operation of State 
Tuberculosis Hospitals and Sanatoria, and assists local 
communities to combat the disease by investigating conditions 
and showing the value of early reporting, dispensary service, 
milk control and other measures. 

Nearly all of the states have recently established a Division 
of Venereal Diseases as a result of the campaign waged by the 
Federal Government subsequent to the passage of the Cham- 
berlain-Kahn Act which offers temporary financial assistance 
to states in the controlling of venereal diseases provided 



PUBLIC HEALTH ADMINISTRATION 205 

proper regulations and a suitable organization are established. 
The organization of a state health department is more or 
less elastic and not all of these divisions are present in every 
state. New divisions may be established and old divisions 
may be abolished to fit the need of the occasion. 

LOCAL HEALTH ADMINISTRATION 

Authority. — Before discussing local health administration 
it may be well to say something about the division of authority 
between the state and local governments since their relation- 
ships are widely varying. In Pennsylvania for example there 
is a centralized system. The local organization is under the 
control of the state organization. In Massachusetts the Legis- 
lature has given to the state organization only the power to 
advise and investigate with no direct control over the local 
health authorities. In every state the supreme authority is 
the state legislature and it can do as it sees fit in giving power 
to the state organization. 

There are dangers in either of the extremes mentioned. If 
the State Department of Health has power over every local 
health officer it must accept the responsibility for his activi- 
ties and the townspeople have an opportunity to blame the 
state department if anything goes wrong. On the other hand, 
if the State has no power over local health officials, dangerous 
conditions may remain uncorrected because of inefficient and 
careless local administration. We are perhaps tending to- 
ward the more centralized system in the country as a whole 
but it would seem that the system which allows the state de- 
partment limited but not complete control over local author- 
ities or additional power in emergencies is preferable to either 
extreme. In some states, legislation is being enacted giving 
the state department power to administer health in any com- 
munity when the welfare of other communities in the state 
may be endangered or injuriously affected. For example, if 
the quarantine measures of a town are insufficient the state 



20G HYGIENE: DENTAL AND GENERAL 

may step in and make its regulations more strict. This sort of 
law leaves the responsibility for community health with the lo- 
cal or municipal officials but gives the state power to protect 
the health of the whole state whenever it may be endangered 
by local inefficiency. 

Local Health Organization. — In any case the major duty 
of enforcing public health law and maintaining healthful con- 
ditions is with the town or the city. Throughout the country 
there is a fairly uniform local health organization which con- 
sists of a Board of Health with a Health Officer or an Execu- 
tive Secretary. Upon the Health Officer there rests the re- 
sponsibility of administering health and upon the Board of 
Health there rests the responsibility of directing health activ- 
ities. The above discussion of public health laws describes 
the health officer's responsibility and his powers of discretion 
regarding them. 

There is a tendency in some places to place responsibility 
upon the local health officer instead of leaving it with the 
board of health. In some states the health officer may be 
appointed to replace the board of health and in Massachusetts 
there has recently been legislation allowing Local Health De- 
partments to be formed — a type of organization similar to that 
of the state. Here a local Health Commissioner is appointed 
with an advisory committee. This sets the responsibility up- 
on the health officer but gives him the benefit of advice and 
support from a committee or council. 

The activities of a local health department are many and 
varied. It is its duty to enforce all of the state laws regard- 
ing health and disease, and to enforce in addition such ordi- 
nances or local regulations as may be in effect and related to 
public health. 

An important duty of the local department is the main- 
tenance of a public health laboratory where laboratory diag- 
noses for infectious diseases may be made and where exami- 
nations of the water, milk, butter, vinegar and foods are car- 
ried out. Laboratories in small communities usually begin 



PUBLIC HEALTH ADMINISTRATION 207 

with the examination of water and milk, and then add diag- 
noses for diphtheria, tuberculosis, septic sore throat, syphilis 
and other infectious diseases. In addition such a laboratory 
often makes tests for the purchasing department of the city, 
analyzing flour, coal and other substances. 

Other activities include the isolation and quarantine of in- 
fectious diseases, subsequent disinfection where necessary, the 
abatement of nuisances, the supervision of hotels and restau- 
rants, a supervision over sewage and garbage disposal, the su- 
pervision over housing conditions, and the administration of 
special activities such as public health nursing, infant welfare, 
city hospitals, the control of epidemics, the collection of vital 
statistics, the making of regular reports to state department 
of health, and many other matters. The problems of water 
and food supplies, milk control, and waste disposal will be 
considered in special chapters as will, the subject of school 
hygiene. 

The Health Officer. — From such a list of activities it is 
obvious that public health administration involves a variety of 
tasks. The local health officer must know the fundamentals 
of sanitary engineering or sanitation and the important facts 
of hygiene. By training the sanitary engineer or the physi- 
cian is best adapted for this type of work, but either should 
have a supplementary training. Public health administration 
is a distinct calling demanding a knowledge of a different 
group of subjects than go to make up any other profession. 
In this country we are rapidly learning that the public health 
officer must be a specially trained man and the number of men 
with special training in public health is rapidly increasing. 

Unofficial Health Activities. — There are many national 
health organizations in the United States and many local 
health societies interested in specific or general health prob- 
lems. It seems reasonable that the function of these private 
health organizations — and it is a useful function — is to develop 
those phases of health activities which the health department 
of a community is not yet ready to handle or which it cannot 



208 HYGIENE : DENTAL AND GENERAL 

well handle because of the particular problem involved. For 
example, cancer research cannot be carried out by the individ- 
ual community, it might be done by the U. S. Public Health 
Service but excellent work may be done by a society specifi- 
cally interested in the problem. Activities like the prevention 
of tuberculosis, which would reasonably fall under the work 
of the organized health authorities, should be cared for by 
private organizations to that extent to which the local com- 
munity is not able to handle the problem. 

The society of professional public health workers is the 
American Public Health Association. It includes not only 
the majority of people professionally engaged in public health 
but an increasingly large number of people with special pub- 
lic health interests. Its official organ is the American Journal 
of Public Health. 

Other societies and health organizations of national impor- 
tance include: The American Red Cross, Department of 
Health Service, Washington, D. C. ; The American Association 
of Industrial Physicians and Surgeons, Harrisburg, Pa. ; The 
American School Hygiene Association, Albany, N. Y. ; The 
American Social Hygiene Association, 105 West 40th St., 
New York City; The American Society for the Control of 
Cancer, New York City; The Child Health Organization, New 
York City; The International Health Commission, New York 
City; The Life Extension Institute, New York City; The Na- 
tional Child Welfare Association, New York City; The Na- 
tional Committee for the Prevention of Blindness, New York 
City; The National Committee for Mental Hygiene, New York 
City ; The National Committee on Malaria, Birmingham, Ala- 
bama; The National Organization for Public Health Nursing, 
New York City; The National Tuberculosis Association, Bal- 
timore, Md.; and The Russell Sage Foundation, Battle Creek, 
Michigan. 



CHAPTER XI 

FOOD CONTROL 

Thus far we have considered food from the standpoint of 
diet. Under food control we shall consider the adulteration 
and sanitation of foods. 

FOOD ADULTERATION 

Cost of Adulteration. — It might be said that the prevention 
of food adulteration is more for the purpose of protecting the 
pocketbook than for protecting the health. The fraud prac- 
ticed in food adulteration may sometimes be harmless but, if 
the adulteration reduces the nutritive quality of a food and 
adds some poisonous or infected substance the culprit who 
practices food adulteration not only robs the consumer but at- 
tacks his health. 

Some people have the mistaken impression that almost all 
food is adulterated. Although the amount of adulteration 
varies in different states according to the nature of the Pure 
Food Law and the efficiency of law enforcement, still the foods 
which are adulterated are greatly in the minority. Consider- 
ing the country at large it has been estimated that 15 per cent 
of the food consumed is adulterated. If this is true, based 
on an estimate of a $3.00 weekly expenditure per capita, the 
people of the United States are paying about two and a half 
billion dollars a year for adulterated, low grade or inferior 
food. If we accept the figures of experts who estimate that 
2 per cent of adulterated food is injurious to health we find 
that the American people are paying yearly over $46,000,000 
for food which actually brings them definite physical injury. 
Comparing present conditions with expert studies made sev- 
eral years ago it appears that Massachusetts saves over a mil- 

209 



210 HYGIENE: DENTAL AND GENERAL 

lion dollars for the public annually by the enforcement of the 
Pure Food Law. 

Nature and Cause of Adulteration. — Food adulteration 
has now become a highly specialized art. Mixing sand with 
sugar and making milk out of chalk are not practiced because 
the detection of such simple fraud is too easy. The man who 
adulterates food now employs the skill of the chemist and an 
ingenuity equal to that of the theater " make-up man" in 
preparing his products. Coffee has been found which con- 
sisted of molasses and flour molded into the shape of coffee 
berries. American cotton-seed and peanut oil from the south- 
ern states have been sent abroad and refined then returned to 
us as pure Mediterranean Olive Oil. It is only by combating 
the craft of the manufacturer with the skill of the trained 
analyst that this type of food adulteration can be detected. 

Keen competition and the desire for greater profits are im- 
portant in causing food adulteration. People demand goods 
out of season and foods from distant parts of the world at 
cheap prices. The American wants goods done up in fancy 
packages, stamped with foreign labels, and served in an ex- 
travagant fashion. It is no wonder that many food manu- 
facturers have discovered with Barnum that "the public likes 
to be humbugged." 

Pure Food Laws. — It is not the purpose of a Pure Food 
Law to prohibit the making of cheap foods or even of second 
quality foods, but it does insist that these foods shall be sold 
for what they really are and not passed off upon the public 
for first quality materials. It is good to have second quality 
foods in the market if they are clean and wholesome because 
they are inexpensive. For example, catsup which is made 
largely from tomato skins, may be nearly as good as that 
made from the fleshy part or inside of the tomato, provided 
that the material is properly washed and sterilized; for the 
difference in food value in a condiment is not important. 
What we wish to prevent is the use of dirty tomato skins pre- 
pared in an unsanitary manner or the sale of second grade 



FOOD CONTROL 211 

catsup under misleading labels. The public is entitled to 
know what it is buying. 

According to the Federal Pure Food and Drug Act which 
was passed in 1906 a substance is considered adulterated : 

(1) If a substance has been mixed with it to reduce the 
quality or strength. (Cocoa shells mixed with cocoa or choc- 
olate, or watered milk.) 

(2) If any substance has been substituted wholly or in 
part. (Cottonseed oil for olive oil, cane sugar for maple 
sugar. ) 

(3) If a valuable constituent has been wholly or partly 
abstracted. (Skimmed milk.) 

(4) If it is mixed, colored, powdered, coated or stained in 
any manner whereby inferiority is concealed. (Lemon ex- 
tract colored with a yellow dye, bleached flour.) 

(5) If it contains any added poisonous or any other added 
ingredient deleterious to health. (Formaldehyde, arsenic, 
lead, salicylic acid, boric acid or benzoates.) 

(6) If it consists in whole or in part of a filthy, decom- 
posed or putrid animal or vegetable substance, or any portion 
of an animal unfit for food or if it is the product of a diseased 
animal, or one that has died otherwise than by slaughter. 
(Oysters contaminated with sewage, wormy figs, embalmed 
beef, etc.) [Under this clause reasonable sanitary require- 
ments can be enforced.] 

The reason certain foods continue to be adulterated in spite 
of this law is because the adulteration is so difficult to detect. 
For example, the sugar of the maple is identical chemically 
with cane sugar and it has been impossible to detect the fraud. 
The result is that more Vermont maple sugar is made outside 
the state than all the trees in Vermont could produce. New 
"Vermont maple sugar" appears in the market long before 
the sap starts in the maple groves of New England. A Con- 
gressional Committee was once told of the experience of a 
Chicago firm which had sent to the trade 150 barrels of pure 
maple syrup. Of this 147 barrels were returned with the 



212 hygiene: dental and general 

complaint that it was too strong. Mixed with cane syrup 
this same lot was again sent out and only praise was had from 
the buyers. 

Misbranding. — The Food and Drugs Act requires that no 
drug or article of food shall be falsely labelled as to its con- 
tents or as to the state or country in which it is manufactured 
or produced. A food is deemed to be misbranded : 

(1) If it be an imitation of or offered for sale under the distinctive 
name of another article. 

(2) If it be labeled or branded so as to deceive or mislead the pur- 
chaser, or purport to be a foreign product when not so, or if the con- 
tents of the package as originally put up shall have been removed, in 
whole or in part, and other contents shall have been placed in such 
package, or if it fail to bear a statement on the label of the quantity 
or proportion of any morphine, opium, cocaine, heroin, alpha or beta 
eucaine, chloroform, cannabis indica, chloral hydrate, or acetanilide, 
or any derivative or. preparation of any such substances contained 
therein. 

(3) If in package form, and the contents are stated in terms of 
weight or measure, they are not plainly and correctly stated on the 
outside of the package. 

(4) If the package containing it or its label shall bear any state- 
ment, design or device regarding the ingredients or the substances 
contained therein, which statement, design or device shall be false or 
misleading in any particular. 

Law Enforcement. — The Federal Food and Drug Act ap- 
plies only to foods imported or for interstate shipment. For 
such food products inspections are made and enforcement is 
secured by the United States Department of Agriculture. The 
purity of foods sold within the state is controlled by special 
state laws and these laws are enforced by state officials. Mass- 
achusetts has long maintained an efficient Division of Food 
and Drugs under the State Department of Health. The 
samples are collected in various parts of the state by inspec- 
tors, each sample is numbered by the inspector who places it 
in a locker in the partition wall of the laboratory. The in- 
spector himself never enters the laboratory but opens the 
locker from the outside. Later the locker is opened from the 



• • FOOD CONTROL 213 

inside by the laboratory technician and an analysis is made, 
the report being rendered on the basis of the number used. 
In this way every suspicion of collusion between the inspector 
and analyst is avoided. 

The state laws are usually similar to the Federal Food and 
Drug Act but frequently include additional regulations re- 
garding special foods like milk, butter, sausages, etc. The 
state which fails to make and enforce suitable laws is in a 
particularly unfortunate condition because large food manu- 
facturers dump poor products upon it. 

Special standards for foods like milk, butter and vinegar 
may also be obtained by municipal ordinance and such foods 
may be examined in the city public health laboratory. The 
most common local ordinance is that governing the sale of 
milk, the skimming or watering of which is determined by a 
variation from the normal proportion of the constituents pro- 
duced by such a process. The composition of normal milk is 
as follows : Sugar 4.7% ; fat 3.8% ; total solids, 12.8% ; refrac- 
tive index, 37.5; solids not fat, 9%; specific gravity, 1.032; 
protein, 3.6% ; ash, 0.7%. 

FOOD SANITATION 

The three most important problems in securing clean food 
involve the sanitation of milk, meat and prepared food sup- 
plies. 

Milk. — Milk is used in enormous quantities as a food. 
Parker believes ( City Milk Supply, by H. M. Parker, McGraw- 
Hill Book Co., 1917) that about 5.16 billion pounds of market 
milk are consumed in this country annually. This means 
that the average American consumes his own weight in market 
milk every year. Of course, children use relatively more than 
adults. The total quantity of milk used in the United States 
including milk which is manufactured into butter, cheese, and 
other materials is estimated to be 77.4 billion pounds per an- 
num. This is about 750 pounds per person. 




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216 HYGIENE: DENTAL AND GENERAL 

It is difficult to keep milk in a sanitary condition because it 
is not a clear fluid but a suspension which hides dirt readily. 
It is a good medium for bacteria to grow in, so that they rap- 
idly increase unless the milk is kept at a low temperature. 
Moreover, milk must be produced at a considerable distance 
from the point where it is finally used. Some of our large 
cities get milk from farms 300 miles distant. And it is par- 
ticularly important that it should be kept clean because milk 
is the one animal food which is eaten raw in great quantities. 

Bacteria which are not disease-producing cause two kinds 
of changes in milk, putrefaction and fermentation. Fermen- 
tation usually results from the action of the lactic acid bacil- 
lus and produces the normal condition of sour milk by break- 
ing down the milk sugar into lactic acid. Milk sours be- 
cause the condition or time of storage has favored the develop- 
ment of acid forming bacteria, its taste may be disagreeable 
but it is not injurious to the health. Indeed specially fer- 
mented milk has been recommended as healthful. When milk 
undergoes putrefaction the proteins are attacked by bacteria. 
Such milk is alkaline in reaction and bitter to the taste. It 
may be injurious to health. 

There are always many harmless bacteria in milk but it may 
also contain the germs of communicable diseases. Everyone 
has heard of milk borne epidemics. Diseases from animals pro- 
ducing milk epidemics include tuberculosis, milk sickness, 
malta fever, hoof and mouth disease, contagious abortion, and 
various streptococcus infections. The diseases which may be 
transmitted from man in milk are tuberculosis, typhoid fever, 
scarlet fever, diphtheria, septic sore throat, dysentery and 
diarrhea. The germs of these diseases increase in number 
rather than die out in milk and it is extremely important that 
both the cows and the milk handlers should be free from such 
diseases. 

An idea of the details which have to be considered in 
producing clean milk may be obtained from an examination 



FOOD CONTROL 



217 



of the "Official Score Card," used by the United States De- 
partment of Agriculture for the purpose of rating dairy 
farms. (See pp. 214 and 215.) 

The problems of the health department do not end here 
however, because the milk must be kept cool and clean from 



TIML AND TLMPLRATURE. FOR 
MILK PA5TE.URIZATIOIN. 




Fig. 



20' 30' 40' 

Tl ME. IN MINUTL5 

30. — Chart showing tin- time and temperatures at which bacteria arc killed and 
at which the quality of the milk is changed. 



218 HYGIENE: DENTAL AND GENERAL 

the time it leaves the farm until it reaches the consumer. 
Frequently milk is a long time in transit and often it is re- 
bottled before being finally delivered. 

Pasteurization has greatly improved the milk supply of 
many cities as it has become more and more widely adopted. 
This process of heating the milk to a temperature of from 
64° to 68° Centigrade for 20 minutes kills most non-spore- 




Fig. 31. — Milk may be pasteurized at home by setting the bottles in a deep 
dish of water or double-cooker and raising the temperature of the milk to 145° for 
a half hour. 

bearing organisms. It is most valuable when the milk is pas- 
teurized in the final container. If the temperatures do not 
go above 68° Centigrade the composition and taste of the milk 
are not changed. 

Graded Milk. — Terms which are often used to describe 
various grades of milk are: Certified Milk, Inspected milk, 
and Market Milk. 



FOOD CONTROL 219 

The American Association of Medical Milk Commissions 
(See Public Health Reports No. 85, May 1, 1912) has set the 
standards for Certified Milk. Such milk is certified by a 
Medical Milk Commission to be produced from healthy, tuber- 
culin-tested cattle which are subject to veterinary inspection. 
The milkers and the milk handlers are given physical exami- 
nations to see that they have no communicable diseases, the 
cattle are kept clean and are given proper food; proper sani- 
tary precautions are taken during, milking, the barn is clean, 
the milk is cleanly bottled at the dairy and kept cold. The 
bacterial count of such milk is less than 10,000 per c.c. It is 
delivered within 36 hours after it is produced. 

Inspected Milk is of a somewhat lower grade but it comes 
from tested cows and it is secured and marketed under cleanly 
conditions. The bacterial count of such milk is less than 
100,000 bacteria per c.c. 

The term Market Milk is often used to describe milk which 
is below the standard of either of the above grades. 

Some years ago New York City began to grade its milk sup- 
ply and this practice has noAV been taken up by many other 
cities with profitable results. Grading milk has the. advantage 
of allowing the purchaser to know the exact quality of the milk 
he is buying and of enabling the dairyman to get a higher 
price for a superior product. The table on pp. 220 and 221 
from Public Health Leaflet No. 1 of the City Health Depart- 
ment shows the standard set for milk of the various grades A, 
B, and C. 

Remade Milk. — Remade milk is a new product which is 
being used by hospitals and other institutions with good re- 
sults. This is made by mixing dehydrated skimmed milk 
(milk powder) and unsalted butter or milk fat with water 
in an homogenizer. By this process milk may be dehydrated 
in dairy regions far from the cities and remade in the large 
centers of population producing a clean, and inexpensive 
product. Remade milk has a low bacterial count and a good 
cream line. It is not easily distinguishable from fresh milk. 



220 



HYGIENE: DENTAL AND GENERAL 



REGULATIONS GOVERNING THE GRADES AND DESIGNATION OF MILK 

The following classifications apply to milk and cream. The regulations regarding 



GRADES OF 

MILK OR 

CREAM 

WHICH MAY 

BE SOLD IN 

THE CITY OF 

NEW YORK 


DEFINITION 


TUBERCULIN 
TEST AND 
PHYSICAL 
CONDITION 


BACTERIAL CONTENTS 


GRADE A 

Milk or Cream 
(Raw) 


Grade A milk or cream (raw) is 
milk or cream produced and handled 
in accordance with the requirements, 
rules and regulations of the Depart- 
ment of Health for that grade. 


1 Only such 
cows shall be ad- 
mitted to the 
herd as have not 
reacted to a 
diagnostic injec- 
tion of tubercu- 
lin and are in 
good physical 
condition. 

2. All cows 
shall be tested 
annually with 
tuberculin and 
all reacting ani- 
mals shall be ex- 
cluded from the 
herd. 


Grade A milk (Raw) shall not 
contain more than 30,000 bac- 
teria per c. c. and cream more 
than 150,000 bacteria per o. c. 
when delivered to the consumer 
or at any time prior to such de- 
livery 


Milk'or Cream 
(Pasteurized) 


Grade A milk or cream (pasteur- 
ized) is milk or cream produced, 
handled and pasteurized in conformity 
with the requirements, rules and regu- 
lations of the Department of Health 
for that grade. 


No tuberculin 
test required but 
cows must be 
healthy as dis- 
closed by physi- 
cal examination 
made annually. 


Grade A milk (pasteurized) 
shall not contain more than 30,- 
000 bacteria per c. c. and cream 
(pasteurized) more than 150,000 
bacteria per c. c. when delivered 
to the consumer or at any time 
after pasteurization and prior to 
such delivery. 

No milk supply averaging 
more than 200,000 bacteria per 
c. c. shall be pasteurized in this 
city for sale under this designa- 
tion. 

.No milk supply averaging 
more than 100,000 bacteria per 
c. c. shall be pasteurized outside 

of this oity for oalo in thio city 

under this designation. 


GRADE B 

Milk or Cream 
(Pasteurized) 


Grade B milk or cream (pasteur- 
ized) is milk or cream produced, 
handled and pasteurized in conformity 
with the requirements, rules and regu- 
lations of the Department of Health 
for that grade 


No tuberculin 
test required but 
cows must be 
healthy as dis- 
closed by physi- 
cal examination 
made annually. 


No milk under this grade shall 
contain more than ICO.OOO bac- 
teria per c. c. and no cream shall 
contain more than 500,000 bao- 
teria per c. c. when delivered to 
the consumer or at any time 
after pasteurization and prior to 
such delivery. 

No milk supply averaging 
more than 1,500,000 bacteria per 
c. c. shall be pasteurized in this 
city for sale under this desig- 
nation. 

No milk supply averaging 
more than 300,000 bacteria per 
c. c. shall be pasteurized outside 
of this city for sale under this 
designation. 


GRADE C 

Milk or Cream 
(Pasteurized) 
(for cooking 
and manu- 
facturing pur- 
poses only). 


Grade C mirk or cream (pasteur- 
ized) is milk or crea'm produced, 
handled and pasteurized in accordance 
with the requirements, rules and regu- 
lations of the Department of Health, 
for that grade 


No tuberculin 
test required but 
cows must . be 
healthy as dis- 
closed by physi- 
cal examination 
made annually 


Milk or cream of this grade 
shall not contain an exoeewve 
'number of bacteria. 



and shall be pas 



NOTE.— Sour milk, buttermilk, sour cream, kumyss. matzoon, zoolac and [**£" 
be pasteurized before being put through the process, of souring. Sour cream auau 



FOOD CONTROL 



221 



AND CREAM WHICH MAY BE SOLD IN THE CITY OF NEW YORK 

bacterial content and time of delivery do not apply to sour cream. 



DAIRY 
INSPECTION 

REQUISITES 



Dairies are in- 
spected at least 
four times a year 
by Department in- 
spectors. 

All requisites 
indicated on dairy 
report card used 
by Department of 
Health must be 
complied with 



Dairies are in- 
spected at least 
four times a year 
by Department in- 
spectors. 

All requisites 
indicated on dairy 
report card used 
by Department of 
Health, except tu- 
berculin testing of 
cattle, must be 
complied with 



Dairies must be 
inspected at least 
once a year by in- 
spectors employed 
by operator of 
creamery or pas- 
teurizing plant to 
which milk is de- 
livered. These in- 
spectors must be 
persons satisfac- 
tory to the New 
York City Depart- 
ment of Health, 
and reports sub- 
mitted on ap- 
proved dairy re- 
port cards must be 
kept on file at 
creamery or plant. 
Inspections are 
supervised or 
•checked by De- 
partment inspect- 
ors at intervals 



TIME OF 
DELIVERY 



BOTTLING 



Dairies not 
regular 1 v i n - 
spected. Only a 
small quantity of 
milk of this grade 
is ever sold in the 
city. 



Shall be de- 
livered within 36 
hours, after pro- 
duction 



Shall be de- 
livered within 36 
hours after pas- 
teurization. 



L'nless other- Outer caps of bottles shall 

wise specified in be white and shall contain 

the permit this the words Grade A, Raw, in 

milk or cream black letters in large type, 

shall be delivered and shall state the place of pro- 

to the consumer I duction, date of shipment and 

only in bottles the name and address of the 
dealer 



Unless other- 
wise specified in 
the permit this 
milk or cream 
shall be delivered 
to the consumer 
only in bottles. 



Milk shall be 
delivered within 
48 hours and 
cream within 72 
hours after pas- 
teurization. 



Milk shall be 
delivered within 
48 hours and 
cream within 72 
hours after pas- 
teurization 



May be de- 
livered in cans 
or bottles. 



May be de- 
livered in cans 
only 



* Outer caps of bottles shall 
be white and shall contain 
the words Grade A in black 
letters in large type, date and 
hours between which pasteur- 
ization was completed, place 
where pasteurization was per- 
formed, name of the person, 
firm or corporation offering 
for sale, selling or delivering 
same 



Outer caps of bottles con- 
taining milk and tags affixed 
to cans containing milk or 
cream shall be white and 
marked "Grade B" in bright 
green letters in large type, 
date pasteurization was com- 
pleted, place where pasteur- 
ization was performed, name 
of the person, firm or cor- 
poration offering for sale, 
selling or delivering same. 
Bottles containing cream shall 
be labeled with caps marked 
"Grade B" in bright green 
letters, in large type and 
shall give the place and date 
of bottling and shall give the 
name of person, firm or cor- 
poration offering for sale, 
selling or delivering same. 



Tags affixed to cans shall 
be white and shall be marked 
in red with the words "Grade 
C" in large type and "for 
cooking" in plainly visible 
type, and cans shall have 
properly sealed metal collars, 
painted red on necks. 



PASTEUR- 
IZATION 



Only such 
milk or cream 
shall be re- 
garded as pas- 
teurized as has 
been subjected 
to a tempera- 
ture of 142-145 
deg. Fahr. for 
not less than 30 
minutes 



Only s u ch 
milk or cream 
shall be re- 
garded as pas- 
teurized as has 
been subjected 
to a tempera- 
ture of 142-145 
deg. Fahr. for 
not less than 30 
minutes. 



Only s u o h 
milk or cream 
shall be re- 
garded as pas- 
teurized as ha6 
been subjected 
to a temperature 
of 142-145 deg. 
Fahr for not less 
than 30 minutee. 



products shall not be 
not contain a leas |>' 



nade from uuy milk of a less grade than that de3iguate< 
entage of fata than that designated for cream 



'Grade B" 



222 HYGIENE: DENTAL AND GENERAL 

Meat. — Meat is inspected by Federal, State and Local 
Health Agents, and in large abattoirs an inspection both be- 
fore and after killing is made. One reason for making such 
an inspection is to see that the animal is free from such dis- 
eases as tuberculosis, anthrax, trichinosis, actinomycosis, tape- 
worm, septic and pyemic conditions. Later inspections of 
meat are to make sure that the meat has not become decom- 
posed or infected. There is also a supervision over the proc- 
esses of slaughter to see that the death of the animal is im- 
mediate and painless, that there is an immediate withdrawal 
of blood, that the intestines, hide and hair are promptly re- 
moved and that there is immediate cooling. 

Dangers in Meat. — The important health dangers which 
exist where meat is not inspected are due to the following 
causes : 

(1) Paratyphoid Bacilli. — If animals have had fevers, diar- 
rhea or local suppurations and especially if the conditions of 
slaughter are not clean, meat may have picked up these or- 
ganisms of the typhoid group, which produce diarrheas of 
varying intensities. 

(2) Bacillus Botnlinus. — This bacillus, which produces 
botulism, is an anaerobic, spore-forming saprophyte, which 
grows outside the body and may infect meat and develop in 
sausages which are not kept under sanitary conditions. This 
organism produces an exotoxin which causes the typical 
symptoms of botulism when the infected food is eaten. 

(3) Trichina Spiralis. — The small roundworm which pro- 
duces trichinosis has a normal cycle in rats but the disease 
may extend to swine. When this happens the larvae become 
encysted in the muscle of the pig producing a condition known 
as "measly pork." When such pork is eaten without being 
thoroughly cooked the larvae develop into mature worms in 
the human intestines. Each female produces about 500 living 
young and these embryos penetrate the tissues of the bowels 
and find their way into the muscle of the human subject pro- 
ducing pain, fever, soreness and other symptoms of the disease. 



FOOD CONTROL 223 

Microscopic examination -of meat is fairly successful in de- 
tecting the presence of these parasites. All pork should be 
cooked until it is thoroughly white and hams should be boiled 
for y 2 hour for every kilogram weight to kill the organisms. 

(4) Taenia Solium. — The encysted larvae (bladder worms) 
of the' pork tapeworms may be eaten in pork. This infection 
is particularly dangerous because the larvae develop in man 
and may find their way to important parts of the body such 
as the eye, or the brain. 

(5) Tcenia Saginata. — This tapeworm occurs only in cat- 
tle and in man. The larvae are found embedded in beef and 
when such meat is eaten they develop in the human intestines. 
This tapeworm is not dangerous although it causes anemia 
and is often difficult to expel. Man is infected from un- 
cooked beef while cattle are infected by eggs passed in hu- 
man feces. 

(6) Tcenia Ecliino coccus. — This minute tapeworm of the 
dog frequently infests cattle, swine, horses and sheep, reach- 
ing the digestive tract of the new host in the form of the eggs 
which are passed in the feces of the dog. The embryoes 
develop in the digestive tube, pierce the mucosa and become 
encysted in various tissues and organs of the body. Man like 
the other animals mentioned is infected from the dog by in- 
gesting eggs which are passed in the feces. 

(7) Ptomaine Poisoning. — Much less is heard recently of 
ptomaine poisoning which has been regarded as being pro- 
duced by a poisonous substance formed in the decomposition of 
proteins. Many cases of supposed ptomaine poisoning have 
been found to be infections or intoxications produced by such 
organisms as paratyphoid or botulinus. 

Prepared Food. — The sanitation of prepared food is secured 
through the supervision of restaurants, food stores, and other 
places where food is sold. The score card shown on page 224 
for food stores used by the Health Department of the City of 
Boston shows the factors of cleanliness which are considered. 



224 



HYGIENE: DENTAL AND GENERAL 



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FOOD CONTROL 225 

Two factors not mentioned in such a score card but of ex- 
treme importance in food sanitation at restaurants and hotels 
are the physical examination of food handlers and the method 
of dish washing. A waiter or food handler who is tuber- 
culous or who is a typhoid carrier may infect food prepared 
in the most cleanly kitchen. The case of one such carrier, 
' ' Typhoid Mary, ' ' has become famous. No person harboring 
the germs of typhoid or any other infectious disease should be 
allowed to handle food. The startling discoveries of Dr. 
Gumming, showing how dishes which are not scalded may con- 
vey respiratory diseases, are described in the discussion of 
influenza. Both in the home and in public eating places the 
germs of tuberculosis, common colds, influenza, septic sore 
throat and other diseases are doubtless carried from diseased 
persons to healthy individuals on unscalded dishes much more 
often than we have previously realized. 



CHAPTER XII 

WATER SUPPLY 

The danger of transmitting disease by polluted water has 
been well recognized since the epidemic of the Broad Street 
Well in 1854. We know now, as they did not then, that the 
danger is not from a particular and peculiar poisonous sub- 
stance, but rather from the germs of infectious disease which 
remain alive in the water and reproduce the disease by multi- 
plying in the digestive tract of the individual who has drunk 
thereof. Water-borne epidemics of typhoid fever, cholera, and 
diarrhea have been so numerous and so important that the 
people at large now have a very keen appreciation of the 
danger from a polluted water supply. 

Although freedom from disease germs is a most important 
characteristic of good water, there are many other important 
considerations in securing a city water supply. Indeed if 
disease germs were the only menace, that danger could be 
avoided by always boiling water before drinking it. Such a 
precaution is used by travelers and explorers where the source 
of water is unknown. In China, where the population is 
dense, most of the wells are polluted and the people are saved 
from intestinal disease by their tea-drinking habit, through 
which they avoid the use of raw or unboiled water. 

Important as water is for the body there are many ways in 
which it is used outside the diet and it is because so much is 
needed that it is difficult to secure a satisfactory supply. The 
average American city uses 100 gallons of water a day for 
every inhabitant. Water has the property of picking up dirt 
so readily and the outlying districts of cities become settled 
so soon that the water shed or drainage basin from which 
water would naturally be secured contains many habitations 

226 



WATER SUPPLY 227 

and the opportunities for pollution with human or animal 
waste are innumerable. 

What Is Good Water? — The characteristics of a good water 
supply may be enumerated as follows : 

1. It should be free from the germs of infectious disease. 

2. It should oe free from poisonous metals, particularly 
lead. It is well known that lead is a cumulative poison which 
is readily taken up by the body in small quantities and which 
has serious effects particularly upon the stomach and the nerv- 
ous system. "Painter's colic" and "wrist-drop" are typical 
symptoms of this type of poisoning. Some waters have a 
much greater solvent action upon lead pipe than others. 

3. The water should he of suitable temperature, certainly 
less than 80°F. If the water is too warm it will not be used 
as much as it should be for drinking purposes. 

4. Tlie water should oe low in color, otherwise it will not be 
acceptable. Color may be harmless but a highly colored water 
will not be generously used. 

5. It should be clear, i.e., free from suspended matter, like 
sand or clay. 

6. It should be odorless. The odor of water most frequently 
comes from small or microscopic plants which grow in the 
lake or reservoir and which of themselves are entirely harm- 
less. The odors which they produce, however, are distinctly 
disagreeable and may make the water offensive. 

7. Tlie water should not be too hard, since hard water makes 
laundering particularly difficult. This is caused by the re- 
action of the calcium or magnesium salts of hard water in dis- 
placing the sodium of soap. Such a reaction forms a pre- 
cipitate of the above, mentioned salts and enough soap must 
be added to use up all the calcium and magnesium in the water 
before any lather is produced. Hard water is therefore un- 
pleasant to use on the flesh and costly for laundering purposes. 

8. It should be practically free from iron. Otherwise 
clothes will be stained or "rusted" in the laundering process. 



228 HYGIENE: DENTAL AND GENERAL 

Sources of Water Supply.— There are two kinds of water 
supplies, surface waters and ground waters. We can better 
appreciate their differences if we follow the history of water 
after it falls as rain. It may fall directly into rivers or lakes, 
or it may reach them by running over the surface of the 
ground. More often it reaches them by soaking through the 
soil just beneath the surface, for ground water is always in 
motion, moving from 0.2' to 20' per day, toward visible or 
underground rivers or in the direction of their flow. Water 
taken directly from rivers and lakes or temporarily stored in 
reservoirs constitutes a surface water supply. 

Surface Water, which has washed over the ground and 
which in rivers and lakes furnishes the home for innumerable 
plants and animals, naturally contains many things besides 
hydrogen and oxygen; in fact chemically pure water is diffi- 
cult to secure even in the laboratory. In nature water which 
appears perfectly clear to the eye may reveal many things 
upon chemical and microscopic examination. It contains dis- 
solved oxygen, upon which the fish and other animals live, 
nitrates and other salts used by plants, carbon dioxide and per- 
haps ammonia, marsh gas and other chemical substances. An 
examination with the microscope reveals particles of dirt, 
bacteria, minute plants and animals, bits of wood and fibers 
of one sort or another. If this water has passed over polluted 
ground, filth and disease germs may be added to its contents. 

Ground Water is obtained from wells of various depths and 
may be free from many of these substances, which are caught 
and held back as the water strains through the soil. Sandy 
or gravelly soil is the best filter for water, and in passing 
through 100 feet of sandy soil water will be purified for a con- 
siderable period. Finally, however, even this soil would be- 
come polluted and a well 100 feet from a privy or other 
source of pollution would be endangered. When in place of 
sand we have a broken formation, as is the case with limestone 
or some types of ledge, there may be a break having a rivulet 
by which pollution may reach the well directly. 



WATER SUPPLY 



229 



The difference between surface wells and deep wells is one 
of character and not primarily one of depth. A surface well 
is one which does not reach through the first impenetrable 
layer of soil ; while a deep well does go through the impervious 
layer and furnishes its water from the water table. A deep 
well may be a quiet well from which the water is pumped, or 
it may be an artesian well from which the water flows freely. 
The artesian well is produced by a water pressure beneath 




Fig. 32. — Wells may be polluted by water which soaks through the soil from 
privies or cesspools. The danger of pollution is less in sand and gravel soil but 
these may finally become saturated and permit infection. (The Human Mecha- 
nism.) 



the impervious layer of soil which is sufficient to throw water 
to the surface. 

Well water has been used for generations. It is usually 
clear, cold and sparkling and most people believe that well 
waters are almost always safe. The contrary, however, is 
frequently the case, especially where wells are dug in un- 
sewered villages where the soil is heavily polluted. In fact 
a clear and sparkling water may be more dangerous than the 
yellow and smelly water of a stagnant pond for, as we shall 
see later, water purifies itself by storage. The water from 



230 HYGIENE: DENTAL AND GENERAL 

deep wells is usually more reliable than that from shallow 
wells because it has been in the ground longer and has worked 
its way through the soil for a long distance. Any student 
of bacteriology knows that a glass of water may contain 
thousands of typhoid bacilli without showing the slightest 
trace of sediment. When people generally realize this they 
will cease to judge the quality of drinking water by its ap- 
pearance. 

WATER ANALYSIS 

A careful examination is necessary to really determine 
the quality of a water supply. Such an examination in- 
cludes four factors. A study of (1) the environment, (2) a 
bacteriological examination, (3) a microscopic examination, 
and (4) a chemical examination. 

1. Environment. — In order to estimate the value of water 
the sanitarian must know the nature of the water shed from 
which it comes ; that is, the number of inhabitants in the drain- 
age area, and the nature of the soil and slope of the drainage 
basin. A laboratory examination of the water at some par- 
ticular time might be satisfactory and yet if the water 
came from a populous district with a clay soil and steep 
slopes, a heavy rain might wash great quantities of pollution 
into the stream or lake. 

2. Bacteriological Study. — The second step is the bacte- 
riological examination of a properly secured sample of the 
water. By plating out the water in different dilutions the 
total number of bacteria may be determined and by using 
different temperatures for incubating the petri dish plates the 
number of water bacteria can be contrasted with the number 
that grow well at body temperature. 

Tests* are also made to determine the number of bacillus 



"laboratory directions for making a complete water analysis may be found in 
"Standard Methods of Water Analysis" published by the American Public Health 
Association. Such directions would be out of place in a discussion for dental 
practitioners. However, it does seem advisable to describe the principles involved 
in the interpretation of a water analysis. 



WATER SUPPLY 231 

coli in the water. It is not easy to detect typhoid bacilli or 
other disease germs when they are present bnt the colon ba- 
cillus, which is a normal inhabitant of the intestines, is easy 
to discover and determination of its presence gives a good in- 
dication of the pollution or purity of the water in question. 
Of the various bacteriological tests which are made these two, 
the total bacteria and the presumptive test for B. coli, are 
the most important. 

3. Physical Tests. — The physical tests which are made upon 
water include an examination for odor, temperature, color and 
turbidity. 

The color is expressed in parts per million and is determined 
b}^ comparing the water with a platinum-cobalt standard. 
True color is produced by substances in solution, many of 
which come from vegetable tissues soaking in the water. 

The turbidity is likewise expressed in parts per million and 
is usually determined by comparing the water with a standard 
suspension of silica. It is produced by finely divided sus- 
pended matter like clay, silt and microscopic organisms. 

The odors are described as fishy, vegetable, aromatic, 
grassy, earthy, mouldy, musty, disagreeable, peaty or sweetish. 
They are caused by decomposing organisms, fermenting ma- 
terial, or gases like hydrogen-sulphide or methane. Many of 
the tiny green plants, particularly the diatoms have quite dis- 
tinctive odors. 

It will be seen from the above that the physical examination 
of water tells much about its condition but little about its 
sanitary quality. 

4. Chemical Tests. — The most important chemical tests from 
the sanitary point of view are the tests for nitrogen in its 
various forms and the test for chlorine. The nitrogen tests 
give us an index of the quantity, the nature and the freshness 
of pollution by nitrogenous waste material. The test for chlo- 
rine is a valuable indicator of pollution because in soils free 
from salt deposits the only source of chlorine, except for salt 
mists brought in from the ocean, is the waste of the body. 



232 



HYGIENE: DENTAL AND GENERAL 




WATER SUPPLY 233 

Nitrogen and the Nitrogen Cycle. — To understand the 
meaning of the nitrogen tests we must recall for a moment 
the story of the nitrogen cycle. We find this important ele- 
ment going through an endless chain of changes. Inorganic 
nitrogen is taken up by plants in its simple inorganic condition 
and transformed into plant protein from which in turn it is 
transformed into animal protein by herbivorous animals. 
When these complex proteins from living animals are left 
exposed in the air or in water they return to their simple 
condition by a series of definite oxidation processes. In this 
series of changes the nitrogen is found consecutively in com- 
plex proteins, albuminoid substances, ammonium salts, nitrites 
and nitrates. Special microorganisms carry out the last two 
steps. Ammonium compounds are acted upon by nitroso- 
monas and oxidized to nitrites. Nitrites are oxidized by nitro- 
bacter to nitrates. In making a chemical analysis of water 
we can determine the amount of nitrogen in these various 
conditions. 

The test for nitrites is particularly valuable because the test 
itself is very delicate and because nitrogen passes through the 
nitrite stage very quickly. The analysis will readily deter- 
mine the presence of 0.01 parts of nitrites per million. Even 
this small quantity shows clearly that organic substances are 
being broken up in the water. This is an indication of fresh 
pollution for if the pollution were remote the nitrogen would 
be found in some of its more stable compounds. 

The test for free ammonia determines the amount of nitro- 
gen present in the water as ammonium salts, which are readily 
driven off on the direct distillation of slightly alkaline water. 
A large amount of free ammonia also indicates pollution, al- 
though it may be remote. 

The test for Albuminoid ammonia measures the amount of 
ammonia sel Free Prom nitrogenous organic matter by the 
action <>f boiling alkaline potassium permanganate. This is 
therefore ;i good index of the amount of easily decomposable 
organic matter in the water. It may come from plant sub- 



234 HYGIENE: DENTAL AND GENERAL 

stances or from animal wastes but when it is from a vege- 
table source the water is usually colored and the nitrogenous 
material is more stable. It therefore follows that a colorless 
water should contain less albuminoid ammonia than the yel- 
low waters of natural storage reservoirs. 

Nitrogen in the form of nitrates is the final product of the 
process of oxidation or mineralization. These are the stable 
compounds which are used as food by plants in building up 
the nitrogen to the organic form. If the nitrates are high 
it indicates that a good deal of nitrogen has gone through the 
mineralizing process and therefore a high figure may indicate 
pollution even though it be remote. Good ground water may 
contain more nitrates than surface water because the nitrates 
of ground water are not used up by growing plants. 

By a continued study of water supplies of various sorts a 
set of standards or limits can be set as to the amount of these 
various substances a good water may contain, although in 
every case, the final interpretation of the chemical analysis 
should be made by an expert. In general a safe water should 
not contain more of these substances than is indicated in the 
following table. 

NITROGEN LIMITS IN A SAFE WATER SUPPLY EXPRESSED 
IN PARTS PER MILLION 

Nitrogen as albuminoid ammonia 0.15 (colorless water) 0.4 (colored 

water). 
Nitrogen as free ammonia 0.15. 
Nitrogen as nitrites 0.01. 
Nitrogen as nitrates. 1. (surface water) 2. (ground water). 

Chlorine. — Chlorides occur most]}' as the sodium salt and 
the results are usually expressed in terms of chlorine. As 
stated above waters coming from soils free from salt deposits 
receive chlorine from only two sources, salt mists blown in 
from the ocean and animal wastes, principally urine. (Human 
urine contains about one per cent sodium chloride.) It there- 
fore follows that unpolluted waters near the ocean would con- 



WATER SUPPLY 235 

tain more chlorine than those at some distance from the coast. 
By the analysis of a large number of samples from waters of 
known purity in various parts of a coast state the normal 
amount of chlorine for each particular district can be de- 
termined and if a suspected water contains more than the 
"normal" amount of chlorine it may be justly concluded that 
an additional amount has been derived from pollution. It 
will be seen that it is not the number of parts per million 
of chlorine but the relation of the amount of chlorine to 
the "normal" which is taken into consideration in inter- 
preting this chemical test. 

5. Microscopic Analysis. — "We have seen that disagreeable 
tastes and odors commonly arise from the presence of micro- 
scopic plants and animals in water. Their presence can be 
detected by straining some of the water through sand and then 
washing the microscopic organisms from the sand and examin- 
ing the wash water under the microscope. In investigating 
a prospective water supply it is desirable to know whether it 
contains these troublesome organisms and in testing the water 
of an old supply it is important to learn of any increase in 
numbers or of the sudden appearance of any organism; be- 
cause by treating the water with copper sulphate the objection- 
able plants may be killed and the disagreeable tastes and odors 
prevented. 

This examination follows the so-called Sedgwick-Rafter 
process in which 500 c.c. of the water is filtered through sand 
from which the organisms are washed with 5 c.c of wash 
water. This concentrated sample is examined on a special 
slide in which the water is just one millimeter deep. A 
special micrometer is used in the microscope to mark off a 
field one millimeter square so that in looking through the 
microscope the number of organisms in a cubic millimeter of 
the concentrated sample may be determined. By counting a 
number of fields a fair average may be obtained and the num- 
ber of organisms in the original sample may be computed. 
This test is regularly made in city water laboratories because 



236 HYGIENE: DENTAL AND GENERAL 

the number of objectionable organisms varies at each season 
of the year and it is important to determine their increase 
before a nuisance is produced. 

By the above tests the sanitary and aesthetic quality of a 
drinking water supply may be accurately determined and by 
the addition of special tests for hardness, iron, etc., its fitness 
for industrial purposes may be estimated. It is hardly neces- 
sary to repeat that the quality of a drinking water cannot be 
determined by its appearance to the naked eye. 

WATER PURIFICATION 

It frequently happens that safe water supplies are not avail- 
able and some method of purifying the water must be adopted. 
There are three important methods in general use: (1) Stor- 
age, (2) Filtration, and (3) Chlorination. 

Storage. — Storage is the natural way of purifying water 
and it is utilized by man in securing water from lakes and 
reservoirs. Bacteria and other particles settle to the bottom 
of standing water and what is often most important the bac- 
teria themselves die of old age or are devoured by other or- 
ganisms. 

It was the privilege of the author to study this process of 
natural purification in a small stream which received the 
partially purified sewage effluent from the city of Brockton, 
Massachusetts. (Reported as (i Studies on the Purification of 
a Seivage Filter Effluent by a Small and Otherwise Unpol- 
luted Stream," by Weston and Turner in Contributions from 
the Sanitary Research Laboratory and Sewage Experiment 
Station, Volume X, M. I. T., Cambridge, Mass., 1917.) This 
study showed that the process of self -purification is largely 
biological and that still water purifies itself much more rap- 
idly than running water, because in the latter case the plants 
and animals which assist in purification processes are swept 
away while in still water they accumulate in enormous num- 
bers. 



WATER SUPPLY 



237 











J-^-^-, 










Monxontai Scale in ^<lz\ 








^S^ 










^^^^ 














i 


s. 








t 

1 




\ 

^ 


r* 




1 

1 






H^ 




1 

1 






-^4: 




! ^ 




o 


*X<£ ^N .CONS UME C 


> 






n 


iSSOUVEP O^VC~EtN 






u 
CL 



*1 *2*3 



*6 



*4. #5 

• Sampling Stations 
Yearly Averages of 
Color, C0 2 ,0 2 Consumed and Dissolved O, 
at Stations *i to*6 Inclusive 

O, r— i , , ,0 



3iF 



«=* 



***5Z. 



Total Nitrog en 



o sooo 

"Horizontal Scala In Fctt 






L 




Sampling Stations 
Yearly Averages of 
Nitrogen as Free nh 3> Aubuminoid NH,, Nitrites, 
Nitrates and Total. N at Stations*? to*6 Inclusive 

Fig. 34. — Diagram showing the condition of the stream studied at Brockton. 
The chart shows the average figures ohtained from weekly analyses of the water at 
each sampling station covering a full year. 



238 



HYGIENE: DENTAL AND GENERAL 



At the point where the pollution enters the stream there is 
a sudden increase in the number of bacteria. These break 
down the organic substances of pollution but they themselves 
are used as food by protozoa which are found in great numbers 
just below the place where the bacteria are most numerous. 
The protozoa in turn are devoured by small Crustacea and 
other higher animals, which are suitable food for fish. The 
abundance of the carbon dioxide and nitrates is removed 



looooo 




Sampling Stations 

Yearly Averages of 

Organisms 



Fig. 35. — Diagram showing the abundance of microorganisms at the various sam- 
pling stations. 

by simple and higher plants which grow in such a quantity 
as to almost clog the stream and furnish protective habita- 
tions for the millions of tiny animals which nature is using 
in the purification process. 

The accompanying diagram shows the effect upon the 
stream produced by introducing the sewage effluent, which 
came in between sampling stations No. 1 and No. 2. The other 
sampling stations indicated in the diagram are approximately 



WATER SUPPLY 



239 




Fig. 36. — This view of the stream taken near Sampling Station No. 4, on July 
21, 1915, shows how completely the higher acquatic plants fill this part of the 
stream in summer. These plants strain out the suspended matter and prevent the 
smaller plants and animals from being carried down-stream. 





; 
f 

; 


! _£=j 


1 









Fig. 37. — A corresponding view January 26, 1916, showing how differently the 
same region appears under winter conditions and high-stream flow. The biological 
processes of purification are greatly reduced. There is greater dilution but less 
purification. 



240 HYGIENE: DENTAL AND GENERAL 

the following distances below station No. 2: No. (3), 980 
feet, No. (3a), 2000 feet,. No. (4), 3650 feet, No. (5), 11,580 
"feet, No. (6), 19,700 feet. 

The storage of water is a simple method of purification and 
is inexpensive except where there may be a high cost for reser- 
voir construction. Experiments indicate that all the disease 
germs usually die out in water which has been stored for a 
month. In reservoirs and in relatively pure waters the bio- 
logical activities are not as intense as in heavily polluted water 
and most of the bacteria are settled out on the bottom or they 
die of old age or lack of food. 

Filtration. — There are two types of filtration for drinking 
water, slow sand filtration and rapid sand 'filtration. In the 
construction of a slow sand filter a concrete floor is first laid 
down and drains with open joints are laid along this imper- 
vious bottom, the joints being covered with small rocks. Then 
the whole filter bottom is covered with gravel to a depth of 
several inches and on top of the gravel there is a layer of 
sand about 3 feet in depth. In cold climates the whole struc- 
ture is placed low in the ground and roofed over with a con- 
crete roof which is covered with soil. This is necessary to 
prevent the surface from freezing up during the winter 
months. 

Such a filter, as the one at Washington, D. C, is made up 
of large units of about one acre each in area. The water is 
1 run onto the sand to a depth of 3 or 4 feet and filters rapidly. 
One acre of filter surface is capable of filtering about three 
million gallons of water per day. This process will remove 
99 per cent of the bacteria and suspended particles and will 
reduce the color 30 per cent. A description of the biological 
principles of the slow sand filtration will be found in the 
chapter on Waste Disposal. 

The rapid sand filter or "mechanical filter" or "American 
Filter" as it is sometimes called, is designed to accomplish 
the purification process with much less sand area. In this 
process a coagulant is first added to the water to produce a 



WATEB SUPPLY 241 

chemical precipitate. The substances commonly used are 
lime and alum which react to produce aluminum hydroxide. 
These chemicals are thoroughly mixed with the water which 
is then passed through a storage tank where the precipitate 
settles out carrying down with it many of the bacteria and 
much of the dirt suspended in the water. 

From the top of this tank the water is drawn off to the filter, 
which in principle of construction, is similar to the slow sand 
filter except that it is much smaller in area and is enclosed in 
a sort of concrete bin. This filter is also supplied with de- 
vices which make it possible to wash the surface of the sand 
by forcing water back up through the filter. This washing 
process must be carried out frequently as the coagulant col- 
lects on the top of the sand and clogs the filter. The bac- 
terial efficiency is about 98 per cent or 99 per cent and it 
operates at the rate of 125 million gallons of water per acre 
per day. 

Chlorination is the third important method of purifying- 
water. Chlorine is added either in the form of chloride of 
lime or as chlorine gas liberated from tubes of liquid chlorine. 
Various chlorinating devices are on the market. In what- 
ever form the chlorine is used enough must be added to kill 
the nonspore-bearing bacteria and care must be taken to avoid 
adding so much as to give a disagreeable taste to the water. 

Sometimes complaints are heard because of chlorine tastes 
in water but the careful operation of chlorine plants should 
make it possible to avoid serious difficulty in this matter. Not 
long ago I had occasion to investigate the water supply of a 
small town. The water was taken directly from the river and 
although chlorination had been going on for nearly a year I 
was informed by the Chairman of the Local Board of Health 
and other citizens that nothing whatever was being done to 
purify the water. Apparently there w r ere no disagreeable 
tastes in this instance. At about the same time a quite dif- 
ferent incident came to my attention a1 another town. It was 
generally known that chlorine was about to be used in the 



242 HYGIENE: DENTAL AND GENERAL 

water although the exact time when treatment would begin 
was not known. Complaints of its disagreeable taste reached 
the Health Officer two days before any chlorine whatever 
was used. 

When the taste of chlorine does occur it is disagreeable but 
sometimes at least complaints are more imaginary than real. 
The amount of chlorine necessary to disinfect a water depends 
upon the amount of organic matter present. Proper methods 
of chlorination render the water practically free from non- 
spore-bearing bacteria. 



CHAPTER XIII 

WASTE DISPOSAL 

Sanitary engineering is a science by itself. But there are 
certain facts and important principles involved in waste 
disposal which any person might well know. We shall 
first describe some of the principles involved in the puri- 
fication of sewage and the disposal of wastes, and then 
discuss some of the problems in waste disposal for a rural 
community or for a residence, because it often happens that 
those who are not sanitary engineers like to know about the 
methods applicable at a camp, a cottage or an institution in 
which they may be interested. By waste disposal we mean 
the disposal of sewage and garbage. 

SEWAGE DISPOSAL 

Sewage is the material discharged into the sewers of a city 
or community and should not be confused with the word 
sewerage which has to do with the sewer pipes themselves. 
Sewage is the material and sewerage the piping system which 
carries the sewage. 

Our consideration will be directed mainly to domestic or 
household sewage, which consists chiefly of excreta mixed with 
the sink wastes, and other waste waters going from the house. 
In city sewage there are also street washings and manufactur- 
ing wastes. 

It is unnecessary to dwell upon the importance of proper 
sewage disposal. In a previous chapter we have seen that 
lack of care in disposing of sewage from houses wiiere there 
are cases of intestinal disease may result in serious epidemics. 
The organisms of such intestinal diseases as typhoid, cholera, 
dysentery, and paratyphoid are discharged in innumerable 

243 



244 HYGIENE: DENTAL AND GENERAL 

quantity in the feces of the patient and may remain alive 
for many days, for weeks even. And wherever drinking 
water, milk or food becomes contaminated with the excreta 
from these patients there is a possibility of spreading the dis- 
ease. So that the first and most important problem in sewage 
disposal is to take such care of excreta that there will be no 
opportunity for spreading infection. But we must not only 
take care of sewage in such a way that germs will be killed 
but also in such a way that it will not produce a nuisance 
in the community. The problem of proper waste disposal 
is not a simple one. 

In considering disposal we need to know the composition 
of sewage. The most important constituent of domestic sew- 
age is the protein and other organic material of the excreta. 
Human excrement is composed largely of bacteria together 
with undigestible products like cellulose and the secretions of 
the mucous lining of the digestive tract, the bile salts and 
special substances like inorganic compounds. Most of this 
material is protein and carbohydrate, with a small amount 
of fat. 

Direct Disposal. — Sewage may be disposed of either di- 
rectly or by purification. In cities located on the seashore 
or on great rivers and lakes disposal by dilution or the di- 
rect discharge of sewage into a large body of water is pos- 
sible. A stream can purify about one-fiftieth of its own vol- 
ume of raw sewage. In the woods or on farms excreta may 
be covered with soil. But in the interior of the country where 
the population is becoming more dense and where all the 
streams are used as drinking water supplies some other method 
of purification must be resorted to. 

Chemical Purification. — Artificial methods of sewage dis- 
posal are by either chemical or bacteriological purification. 
By chemical purification we mean adding some chemical like 
a strong alkali or acid or chlorinated lime to the sewage in 
order to disinfect it. AVe shall cite but three examples of 



WASTE DISPOSAL 



245 



purification by chemical processes ; the chemical closet, chem- 
ical precipitation and the Miles process. 

The Chemical Closet in its simplest form may be used in- 
side the house. It consists of a jar placed in a closed box 
under a toilet seat and containing a strong solution of caustic 
soda which disinfects and partly dissolves the excreta which 
reach the liquid. These closets are nearly free from odor. 
They are made bv dozens of manufacturers in America and 




Fig. 38. —A Chemical I tailed in a home where running- water is not avail- 

able. (Courtesy of The J)ail Steel Products Company, Lansing, Mich.) 

may be obtained either as a single unit consisting of a sin- 
gle seal or as a large unit consisting of several seats over the 
tank. Such installations are now used in many hoys' camps 
and in hunting camps. 

Chemical Precipitation of the solids in sewage is sometimes 
secured bv the addition of chemicals, like lime and alum. 



246 HYGIENE: DENTAL AND GENERAL 

which form a flaky precipitate, carrying down with it the light 
floating particles in the sewage. This precipitation takes 
place in a large chamber or settling basin, the water is drawn 
off from the top and the remaining solids (sludge) are usually 
pressed to expel as much water as possible. The dried sludge 
is hauled out to sea or buried on waste land. It has small 
fertilizer value and is therefore not salable, although at some 
purification works a portion of the sludge is hauled away by 
farmers for fertilizer purposes. 

This process is not much in use at present because chemicals 
are expensive and because the degree of purification secured 
is not high. The liquid effluent from this process is putre- 
factive and needs further treatment unless there is opportu- 
nity for great dilution, the sludge is produced in large quan- 
tity and there is no easy method of securing its final disposal. 

The so-called Miles Process has recently been suggested for 
the treatment of sewage in very large cities. This process 
disinfects the sewage with sulphurous acid, by introducing 
S0 2 into a large tank of sewage and allowing the clear and 
nearly sterile liquid effluent to flow on into the river or the 
ocean at the same time collecting the solid material and fats 
in sedimentation chambers. The proteins settle out at the 
bottom of the tank and may be used as fertilizer base. The 
fats are released by the chemicals and may be skimmed from 
the top of the liquid, purified and sold for soap grease. This 
process is still in the experimental stage but seems to be 
worthy of trial by large cities. 

Bacteriological Purification. — There are two widely dif- 
ferent processes for the bacteriological purification of sewage, 
the aerobic and the anaerobic. It is the presence or absence of 
oxygen that determines which of these two processes will take 
place. 

^Irobic Processes. — The biological principles of aerobic 
purification have already been alluded to in our reference 
to the nitrogen cycle in the discussion of the interpretations of 
the chemical water analysis. When enough oxygen is sup- 



WASTE DISPOSAL 247 

plied to sewage, as it is being broken down by the bacteria 
contained within it, much of the nitrogen is finally converted 
into nitrates through the various descending steps of the nitro- 
gen cycle. Carbon dioxide is also produced in large quan- 
tities. When the process is completed the solid residue of 
the sewage (sludge) has somewhat the consistency of humus 
soil. Practical applications of this principle are found in 
Sewage Farming, Intermittent Sand Filtration, Rock Fil- 
ters and JEration. 

1. Sewage Farming. — It has long been known that it is 
possible to purify sewage by allowing it to flow on to soil 
which is largely sand or gravel. This is merely the utilization 
of the agricultural process of fertilizing land. Near Paris 
many acres of sewage farms have been in operation since 1866. 
Farmers buy sewage from the city securing thereby both 
water and fertilizer. Gates and ditches are built in such a 
way that the flow of sewage may be directed to the desired 
section of the farm. There are smaller sewage farms in 
Europe much older than those in Paris. 

The purification of sewage by this method is almost com- 
plete for the solids are left upon the surface and the water, 
which soaks through the soil and finally makes its way to the 
streams, lakes or rivers, shows little trace of pollution. But 
in order that sewage farming shall be a success the soil must 
be mainly sand or gravel and free from clay, peat and chalk. 
Moreover a great deal of land is required since in American 
cities about an acre of land is necessary to treat the sewage 
of 100 people. The rate of filtration on the sewage farms 
near Paris is 12,000 gallons per acre per day. There are a 
few sewage farms in California where soil and climate are 
favorable, but for the most part American cities use more in- 
tensive methods of sewage disposal. 

2. Intermittent Sand Filth vtio.w — Although earlier and 
limited laboratory studies had been made in England, the 
principle of the purification of sewage by filtration through 
sand was largely developed at the Massachusetts Sewage Ex- 



248 



HYGIENE : DENTAL AND GENERAL 




WASTE DISPOSAL 249 

periment Station, at Lawrence, between 1886 and 1890. In 
these experiments sewage was filtered through several feet of 
sand which had been placed in large round wooden tanks. 
These experiments, which first combined biological, chemical 
and engineering research in behalf of the State and in the in- . 
terest of the public health, form an important and interesting 
chapter in the history of sanitary progress. 

Sand beds as they are now constructed are usually about 
one acre in area and from 1 to 5 feet deep. In making such 
a bed underdrains of tile with open joints are first laid. The 
joints are protected with rocks and gravel to prevent the drain 
from becoming clogged. Then coarse sand is placed over the 
drain to a depth of 2 or 3 feet and fine sand is used for making 
the top of the filter. The bed is flooded with sewage to a 
depth of a few inches and then allowed to dry after which a 
' ' breathing space ' ' of several hours is allowed before a second 
dose of sewage is put on the bed. 

The reason for this intermittent method of dosing the sand 
bed becomes apparent upon a consideration of the biological 
principles involved. It is found that as the bed is used the 
sand grains near the surface become coated with a gelatinous 
growth of the oxidizing bacteria to which the sewage purifica- 
tion is due. This gelatinous coating of the sand grains makes 
the filter more tight and as the coating becomes heavier with 
increased numbers of bacteria the efficiency of the filter rap- 
idly increases. These are aerobic or oxygen breathing bacteria 
and it is therefore necessary to let the filter rest or ' * breathe ' ' 
long enough for oxygen to penetrate into the bed between the 
times when the bed is flooded with sewage. 

A good intermittent sand filter will remove 99 per cent of 
the bacteria of sewage and effect a very high degree of puri- 
fication. In fact the effluent from such a filter is almost a 
"drinking water" effluent. A filter bed one acre in area 
will treat from fifty thousand to one hundred thousand gal- 
lons of sewage per day. in other words one acre of filter 
will provide sewage treatment facilities for about six hundred 
people. 



250 HYGIENE: DENTAL AND GENERAL 

3. Sprinkling Filters. — Sprinkling or percolating filters 
treat sewage nruch more rapidly than intermittent sand niters. 
They make use of the same biological principle of aerobic 
bacterial action but the purification which such filters effect is 
not as complete as in the case of the sand filter. They are 
from 6 to 8 feet deep and are composed of broken stone, coal 
or coke with an effective size of from 1 to 3 inches. This 
broken stone is placed upon a concrete floor which is properly 
drained. The sewage is thrown onto the bed through sprin- 
kler nozzles which spray the sewage into the air in much the 
same way that water is thrown into the air by a lawn sprayer. 
This allows the sewage to accumulate oxygen from the air and 
it is ..also continuously in contact with the air as it trickles 
over the rocks of the porous filter. 

Filters of this type properly constructed and operated may 
be depended upon to remove from 70 per cent to 90 per cent 
of the bacteria and to produce a non-putr-escible liquid effluent. 
This, effluent however contains suspended solids which are 
easily settled out and which are putrescible. The average 
rate of filtration in American filters of this type is about two 
million gallons per acre per day. 

4. Activated Sludge. — A more recent development in the 
treatment of sewage by the aerobic process involves bubbling 
air through the sewage as it passes through a deep tank. A 
few inches above the real bottom of such a tank there is a 
false bottom, which contains many square plates of porous 
tile. Air is forced through these plates in fine bubbles which 
make their way through the sewage to the top of the tank. By 
continually forcing air through the sewage the small par- 
ticles of sludge soon become "activated" by the accumulation 
of mineralizing bacteria so that the rate of nitrate formation 
becomes exceedingly rapid. 

A bacterial removal from 80 per cent to 90 per cent is 
claimed for the process, a liquid effluent of high quality is ob- 
tained and the sludge is nonputrescible and of good fertilizer 
value. 



WASTE DISPOSAL 251 

Anaerobic Processes. — The anasrobic decomposition of sew- 
age which takes place whenever sewage is stored in large 
tanks is quite a different process. Under these conditions the 
available oxygen is soon used np by the aerobic or free-oxygen 
breathing bacteria. Such bacteria soon die for want of oxy- 
gen and there remains only the anaerobic bacteria : those which 
are able to wrest their oxygen from the organic compounds 
undergoing septic action. From such a process three gases 
are produced from the proteins, namely, nitrogen gas, am- 
monia, and hydrogen sulphide. From the carbohydrates some 
carbon dioxide and a greater quantity of marsh gas are pro- 



THE BACTERIAL ACTION IN THE .EROB1C AND ANAEROBIC 
PROCESSES 



Nitrites 



Nitrates 



composition 




Ana rob ic Decomposition 




CO, 


ILS, CII 4 , CO,. N. Nil 


Albuminoid 
Ammonia 

Free l£ 
Ammonia 


*s 


\ se t e /y* 

( Jarbohydratesx^ 
*""■" Proteins ' 
Fats 



Sludge Sludge 



duced. This process results in the reduction of the quantity of 
solids but leaves a residue or sludge which is tarry in consis- 
tency and appearance and is further putrescible. The above 
chart contrasts the anaerobic and aerobic processes. 

1. The Cesspool. — A familiar example of the anaerobic 
purification of sewage is the leaching cesspool which is usually 
built like a well with sides made of large stones between which 
the water may pass into the surrounding soil. The sewage 
solids accumulate at the bottom of this tank and are greatly 
reduced in volume by the septic action of bacteria. 

2. The Septic Tank. — Sometimes a tank with tight cement 
walls is used instead of the leaching cesspool and here there 



252 



HYGIENE : DENTAL AND GENERAL 



is an even better opportunity for anaerobic action to take place. 
Here as in the old style cesspool the quantity of solids is 
greatly reduced but residue must be occasionally removed. 
Large septic tanks are used in the purification of city sewage. 




Fig. 40. — Imhoff Tank. The water flows through the upper chamhers of the 
tank A and B, the flow being reduced by the baffles G ; the upper chamber is sepa- 
rated from the lower or sludge digestion chamber C, by the partition F; the solids 
settle out through the slot J, and the gases escape to the right D, being separated 
from the fresh sewage. (Public Health Bulletin No. 101.) 

3. The Two-story Tank.— More recently this simple tank 
has been improved upon and we have had what we call the 
two-story tank of which perhaps the most important type is 
that known as the Imhoff Tank. The sewage flows slowly 
through the upper chamber and the solids settle to the bottom 



WASTE DISPOSAL 253 

and pass through, the narrow slot into the lower or sludge 
digestion chamber. It is in the lower chamber that the septic 
process takes place and there is an advantage over the single 
story tank in that the gases produced are prevented from pass- 
ing through the fresh sewage. The result is that the effluent 
of such a tank has been freed from solids without losing its 
dissolved oxygen and it is therefore more easily purified 
further by filtration or dilution. The sludge digests for sev- 
eral weeks in the lower chamber and is finally pumped out, 
allowed to dry and is disposed of on waste or agricultural 
land. 

Possibilities and Limitations of Sewage Purification. — 
The above illustrations are intended only to further explain 
the principle of sewage purification. In actual practice two 
or more of these processes may be used jointly and other de- 
vices like grit chambers to remove the sand, and fine or coarse 
screens to remove part of the solids may be added. The sew- 
age of a city might pass successively through screens, septic 
tanks and a trickling filter, after which the effluent might be 
disinfected with chlorine before being allowed to flow into a 
lake or stream. The sanitary engineer must prescribe a treat- 
ment in each case which is adapted to the sewage itself and to 
the condition and location of the city. 

A good example of purification may be found at the city of 
Brockton, Mass. Brockton is an inland city of about 65,000 
population which is not located on or near any large lake, or 
river. The sewage is purified by sprinkling niters and then 
by slow sand filtration, after which the effluent is carried 
into a small brook. The average daily flow of this brook in 
summer is only a half million gallons per day, but so com- 
pletely is the sewage purified that two million gallons of sew- 
age effluent are received daily by the little brook without pro- 
ducing a nuisance. Moreover, studies upon the self-purifica- 
tion of this stream referred to in a previous chapter show that 
the final processes of purification are carried out so swiftly 



254 HYGIENE: DENTAL AND GENERAL 

by the innumerable plants and animals of the "food cycle" 
referred to that two miles below the point where the sewage 
effluent enters, the stream has regained its normal appearance. 
It is possible to purify sewage and discharge the effluent 
into a stream which is soon to be used again as a city water 
supply provided the second city adopts proper methods of 
purification for its drinking water. But there is danger that 
we may go too far in this direction. No one likes to feel that 
he is drinking purified sewage even though the purification 
process is complete and the pollution fairly remote. Further- 
more, in such a case there is the possibility of a slip in the 
purification process and the consequent contamination of the 
drinking water supply. If such a process of purification is 




Fig. 41. — Sewage purification plant at Atlanta, Ga. In the foreground there 
are grit chambers in which the sand is settled out. The water then flows into the 
large Imhoff Tanks beyond and from these tanks the effluent is carried to trickling 
filters some of which are seen in action. To the extreme left a sand bed for dry- 
ing the sludge appears in indistinct outline. 

necessary it is certainly much better- to have sand filters be- 
tween the sewage and the water supply than to rely upon 
other methods of purification or disinfection. A table (see 
p. 255) has been added indicating the pre-war cost and some 
of the facts of construction and operation of the more impor- 
tant methods of sewage purification. 

Rural Sanitation. — The important problems of rural sani- 
tation, that is, the disposal of wastes in rural communities, 
cannot be better presented in the available space than by the 
excellent report of the Committee on Sewerage and Sewage 



WASTE DISPOSAL 



255 



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250 HYGIENE : DENTAL AND GENERAL 

Disposal of the Sanitary Engineering Section of the American 
Public Health Association. The following precise and care- 
fully prepared report presented at the October meeting of the 
Association at New Orleans in October, 1919, is. reproduced 
here through the courtesy of the Association. 

It is well known to those who have spent much time in our rural dis- 
tricts that the vast majority of families retain in use the antiquated 
privy with its menace of typhoid by the contamination, of wells and 
springs, and through the agency of flies; the possible transfer of the 
hookworm, tapeworm and other parasites by contact through the soil 
and vegetable life, and with its attendant obnoxious odors. 

It is true that among the better class of farmers these conditions are 
being ameliorated and in many cases really modern and sanitary meth- 
ods have superseded the objectionable privy; but rural communities as 
a whole are conservative and progress in such, matters is slow. 

For instance, it was found upon an inspection by the United States 
Health Service in 72 towns of populations varying from 500 to 20,000 
located in 15 representative counties of 13 different states, but one 
was ' ' free from grossly insanitary privies. ' ' In Connecticut ' ' of the 
15 to 20 analyses of wells received in this office (of the State Depart- 
ment of Health) each week, practically 95 per cent show evidence of 
contamination. ' ; In Indiana 60 per cent of the shallow wells have 
been found impure, and in Wisconsin, which is certainly not a retro- 
grade state in regard to sanitary matters, it has been found that from 
30 to 40 per cent of the water supplies on farms contain B. coli, in- 
dicating contamination by barnyard drainage. 

For this, reason the committee has taken Mural Sanitation as applied 
to the Collection and Disposal of Nightsoil, Sewage and Garbage as a 
fit and timely subject for report. A further reason for its selection 
lies in the fact that, while there is much valuable literature on the sub- 
ject, particularly in the bulletins of boards of health, the information 
remains scattered, unrelated and unstandardized. 

It is hoped that by presenting a few typical and inexpensive meth- 
ods to be followed and devices to be recommended for the disposal 
of rural wastes from a limited number of individuals and under ordi- 
nary conditions, this report may serve a useful purpose as a guide to 
the householder, physician and local health officer. 

The object to be obtained and the methods to be employed may be 
categorically outlined as follows: 



WASTE DISPOSAL 257 

Object 

To collect and dispose of nightsoil, sewage and garbage in rural 
communities : 

(a) "Without danger to health by 

Contamination of the soil; 

Contamination of vegetables; 

Contamination of water or ice supplies; 

Direct contact; 

Indirect contact (flies, mosquitoes, vermin). 

(b) Without the dissemination of offensive or disagreeable odors. 

(c) Without offense to sight by 

Lack of privacy; 

Exposure of dejecta; 

Day removal of nightsoil near habitations. 

(d) Without breeding or attracting undesirable insects or vermin. 

(e) With the maximum of convenience and comfort. 

(f) Without unnecessary expense — 

First cost may often be reduced by obtaining expert advice. 
Operating costs may be kept down by providing efficient super- 
vision (effect of frost, repairs, utilization as fertilizer). 

Methods 

1. Disposal of nightsoil or dry disposal 

(a) The straddle trench 

(b) The pit privy 
Movable or temporary 
Fixed or permanent 

(c) The receptacle (pail, tub or box) privy 

(d) The chemical closet 

2. Disposal of sewage or wet disposal 

(a) The cesspool. No outlet provided 
Pervious 

Impervious 

(b) The tank. Outlet provided 
Plain settling 

Septic 
Imhoff 
Followed by 
Dilution 

Surface irrigation 
Subsurface irrigation 
Sand filtration 
Trickling filters 
Contact beds and sometimes also by disinfection 



258 hygiene: dental and general 

(c) The soakage or absorption pit for 
Urine 
Slops 

3. Disposal of garbage 

(a) By rilling in land 

(b) By burial 

(c) By use as fertilizer on the land 

(d) By burning 

(e) By reduction for recovery of grease and tankage 

(f) By feeding to hogs 

4. Disposal of manure 

(a) By burning 

(b) As fertilizer 

With prevention of flies during storage 

With protection from flies or direct contact with excrement provided, 
there are few methods of disposal in general use that may not be em- 
ployed under special conditions as to remoteness from habitations, 
water supplies or cultivated land. Much depends on the climate, the 
character of the soil and the reliability of maintenance obtainable. 
General principles remain the same for all, but the application may 
differ widely between an isolated construction camp, a farm, a military 
cantonment and the outskirts of a village, and the cost demanded in 
the last instance would in no wise be justified in the first. 

It has not been possible within the scope of the report to go into 
detail regarding special provisions for camps, schools, fair grounds 
or communities involving more than a few individuals but the general 
principles remain the same as for the individual house. 

Dry Disposal 

Disposal on the surface of the soil is inadmissible from every point of 
view, inviting transmission of disease germs by accidental contact, 
through flies, mosquitoes, rats or domestic animals, farm produce and 
water supplies. There is also the danger of transmitting hookworms 
where these are indigenous besides being an offense to sight, smell and 
the sense of decency. 

The Straddle Trench is the most primitive form of sanitary provision, 
and is adapted only to such situations as are found in lumber camps, 
with mobile troops, etc., remote from habitations. The trench is about 
twelve inches in both depth and width and of the necessary length. The 
earth removed is banked on each side, serving as a rest for the feet. 
After use the excreta should be at once covered with earth several 
inches in depth. 



WASTE DISPOSAL 259 

A more desirable device, but suitable only for secluded locations con- 
sists of a cheap and simple Box Seat which may be placed over a pit 
without any superstructure and moved as occasion requires. The box 
should be fly-tight and the lid self closing, in which case the strictly 
sanitary requirements may be met provided care is exercised in select- 
ing the location. 

The Pit Privy is the simplest arrangement that meets the require- 
ments of sanitation and privacy. If improperly built or located it is 
a serious menace to health, especially on account of the transmission 
of pathogenic bacteria by flies, animals and water used for household 
purposes. If permitted to overflow during storms and contaminate the 
surface of the ground, the danger is greatly increased. These objec- 
tions may be overcome by providing: 

A pit of proper depth and capacity. 

A tight superstructure so designed as to prevent the passage of flies 
to or from the pit. 

A floor above the ground level. 

A door and lids to the seats that close when not in use. 

Durable screens over all openings for ventilation. 

If the pit privy is for use in farms, camps, hunting lodges, etc., far 
from other dwellings and sources of water supply, the pit may be left 
pervious, and, when necessary, the superstructure moved to a new lo- 
cation, a pit for which has been prepared in advance. 

The pervious pit should never be used in villages or where the con- 
tamination of wells or other water supplies is possible. In that case 
the pit or vault should be given an impervious lining. The structure 
then becomes more fixed and permanent in character. By constructing 
the vault in two compartments they may be used alternately for several 
months. While resting in a ventilated chamber the contents diminish 
in volume and become easier and less offensive to handle, especially if 
a little dry earth or, better, lime has been added each time the privy 
is used. 

In general, other wastes than excreta should be excluded from the 
pits or vaults or privies. If the vault contains much dilute liquid, 
cleaning is expensive and in warm weather mosquitoes may breed. This 
may be prevented by adding a cupful of petroleum to the contents every 
week or two. 

By providing a removable box seat the pits of latrines or privies 
may be burned out at least three times a week, using a gallon of crude 
oil to fifteen pounds of hay or straw. Otherwise it may be sprayed 
with a mixture of one pound of lampblack to two gallons of kerosene or 
one pound of bone-black to three gallons of crude oil. 



260 



HYGIENE : DENTAL AND GENERAL 



Screens should be durable, of from 1-1 to 18 meshes per inch. If 
painted light blue they repel flies and are difficult to see through from 
the outside. 

The Receptacle Privy, in which a can, pail, box or tray is substituted 
for a pit or vault, has an advantage in the possibility of placing it 
indoors if an outhouse is not available, and in the prompt removal of 
wastes and constant supervision which are then essential. On the other 




Fig. 42. — A single-seated sanitary privy. Front view. (After Stiles.) 



hand, for this very reason, it is less fool-proof than the well-built pit 
privy and so should be used only when someone can be responsible for 
its regular care. 

The receptacle has a capacity preferably of about two cubic feet. It 
should be removed at least once a week in warm weather, or when about 
two-thirds full, and be replaced by a clean receptacle with an inch or 



WASTE DISPOSAL 



261 



so of sawdust or dry earth in the bottom. It may be handled from in- 
side or from the rear of the privy house, and, in order to prevent the 
access of flies, it should fit tight directly under the seat, to which 
position it should be directed by guide strips nailed to the floor. 

The use of any but thin paper should be avoided and after use the 
contents should be sprinkled with lime, ashes or dry earth kept in a 
box or pail convenient for the purpose. The precautions for ventila- 




I-'ig. 43. — Rear and side view of privy shown in Fig. 42. (After Stiles.) 



tion, screening, etc., and, if out of doors, the construction of the super- 
structure are the same as for the pit privy. 

To avoid odor the receptacle should be washed when emptied with a 
10 per cent solution of eresol and the outside, it' of metal, scoured with 
sand and paraffin. 



262 HYGIENE : DENTAL AND GENERAL 

In military camps or where used by careless persons the seats should 
be scrubbed daily with soap and water and at least twice a week with 
a solution of one and one-half ounces of cresol in a gallon of water. 

The necessity of providing for the accession of farm hands during 
the harvesting, berry-picking and canning season is important on ac- 
count of its bearing on the possible contamination of food supplies. 
For such situations a receptacle consisting" of a long trough which can 
be inserted under several seats and withdrawn for cleaning may be 
substituted for the ordinary can. 

If the contents of the cans become frozen so as to render emptying 
difficult, they may be immersed in warm water a few minutes, when 
they are readily emptied. Otherwise a surplus number of cans should 
be provided so that when filled they may be stored until thawed out. 

The out-door privy should be inconspicuous. A trellis or a few shrubs 
before the door will secure this end and improve the general appearance 
of the place as well. 

The Chemical Closet is a receptacle privy in which the contents of 
the receptacle are largely liquefied and sterilized by a strong caustic 
solution, such as a solution of sodium or potassium hydroxide. 

If properly designed and cared for and with proper chemicals it 
may be placed in any convenient place in the house or elsewhere and 
therefore, need never be exposed, inaccessible or uncomfortable. Dan- 
ger of soil pollution or other means of disseminating disease is greatly 
reduced and it is easily ventilated and cleaned. On the other hand, it 
requires the attention demanded of any receptacle privy and, in addi- 
tion, the proper selection and use of the chemical. Where such atten- 
tion is assured, tlie chemical closet is well adapted to the use of invalids, 
schools, institutions and resorts that have no facilities for sewerage. 

The final disposal of nightsoil is quite as important as its collection. 
It should not be accessible to insects, vermin, barnyard fowl or stock, 
or be liable to come in contact with the human person during or after 
removal. It should, therefore, never be placed on the surface of the 
ground. 

Where receptacles are used by villages or cantonments removal should 
be done under some central authority and during transit the nightsoil 
should be kept under cover. 

If a seAverage system is within reach the best plan is to dump the 
nightsoil into one of the sewers. Otherwise, burial in the ground is 
usually the simplest and best method. This is sometimes done by plow- 
ing a furrow, distributing the material in it and plowing under, but 
as there is too great a likelihood of imperfect covering in this way 
it is recommended that this be done by hand. 



WASTE DISPOSAL 263 

A preferable method is to dig a trench from 9 to 18 inches deep (24 
inches in winter), place the nightsoil in this to a depth of from 2 to 4 
inches and backfill at once with at least 4 inches of earth. The bac- 
teria indigenous to the soil at this depth will effectually dispose of the 
material without offense. This method should be carried out in some 
well drained sunny field which will not be put under cultivation within 
six months (twelve months in regions where the hookworm prevails). 
Such a field should not drain toward a well, spring or other source of 
water supply. It should be at least 300 feet therefrom or from any 
dwelling. No hogs, cattle or poultry should have access to land devoted 
to this purpose. In this way 3,600 cubic feet of nightsoil may ordi- 
narily be disposed of per acre of ground. 

Another method of disposal for nightsoil is by incineration with rub- 
bish; or it may be utilized as a fertilizer, preferably first allowing it 
to rot for a year. These methods cannot be recommended, however, on 
account of the danger of odor and flies. 

To deodorize privies, milk of lime should be added to their contents 
once a week, but for the disinfection of nightsoil a solution of one pound 
of chloride of lime in five to eight gallons of water, or a 3 to 5 per 
cent solution of cresol, will be found more effective, using from three- 
fourths to one gallon per cubic foot of nightsoil. 

To prevent the breeding of flies the nightsoil should be sprinkled with 
powdered borax or, better, a solution of one pound of borax to a gal- 
lon of water for every 10 cubic feet of nightsoil, applied once every 10 
days. 

Xo privy should be located within 20 feet of a house ; within 50 feet 
of sleeping or eating quarters in a camp or cantonment; within 50 feet 
of a stream; or, if leaching into the soil is possible, within 200 feet 
of any body of water that may be used for household purposes, or 
upon land draining directly toward a well, spring or stream thus used. 

Wet Disposal 

The Cesspool is, in effect a deep pit privy with a pervious lining. 
If impervious it is practically a crude form of septic tank and there 
appears no good reason why a well-designed tank should not be pre- 
ferred in every case. 

Cesspools arc usually from 7 to 12 or more feet in depth and the 
minimum capacity may be placed at about 80 cubic feet. They per- 
mit gross pollution of the subsoil and so should be only used in remote 
regions and where the water supply is brought from a higher level and 
from a considerable distance, depending en the formation. They should 
not be used where the ground water stands within Id feet of the 
surface, or where, as in limestone regions, natural underground channels 
may exist. 



264 HYGIENE: DENTAL AND GENERAL 

As with the pit privy, surface water should be rigidly excluded, the 
structure made entirely flyproof, and the same methods should be ap- 
plied for disinfection. 

The cesspool should be cleaned when filled to within not less than 2 
feet of the top. This may be accomplished pneumatically by employing 
a portable ' ' odorless excavator ' ' which conveys the material to the 
nearest sewer or to a field for irrigation, but to avoid handling large 
volumes of liquid that fail to leach into the ground this may be per- 
mitted to overflow to a line of subsoil distribution tile or to a specially 
prepared bed of gravel or cinders, from which it will gradually soak into 
the surrounding soil. 

If used as a fertilizer by irrigating the land this should only be done 
in dry sunny weather, on pervious land located at a distance of at least 
a quarter of a mile from any dwelling and on which only trees, shrubs, 
grain or root crops are cultivated, and where these are not to be har- 
vested within a month. 

The Septic tank is the type of tank generally to be recommended for 
isolated houses having a public water supply and a soil favorable for 
subsoil irrigation for the effluent. Otherwise resort must be had to 
some form of dry disposal. 

For single houses the capacity, including space for sludge, should 
equal the volume of sewage to be received in about 36 hours, or say 10 
cubic feet for each person. 

No surface or roof water should be admitted. 

To maintain a favorable temperature in the winter the surface of 
the sewage in the tank should, if possible be below the frost line. 

The tank may consist of two chambers or of a single chamber with 
baffles, and for small installations it should be covered. Hopper bot- 
toms with sludge outlet pipes facilitate the collection and removal of 
sludge but usually add to the cost. 

Inlet and outlet pipes should terminate from 12 to 24 inches below 
the surface of the sewage. 

Gas vents should be provided. 

Only thin toilet paper should be used. 

No disinfectant should be employed, but a thin film of oil may be 
kept on the surface to prevent odor and the breeding of mosquitoes. 

The tank should be cleaned annually. 

To promote bacterial activity a few pints of sludge from a neighbor- 
ing tank or a little stable manure should be placed in the tank when 
first used. 

The Imhoff tanlc is to be preferred to the septic tank for larger in- 
stallations, such as institutions, hotels, etc., as there is less liability to 
offense in the disposal of the sludge. The period of retention should 



WASTE DISPOSAL 265 

be from 5 to 20 hours, depending on the number of persons served. In 
other respects the rules given for septic tanks only apply. 

The effluent from either type of tank may pass to a body of water 
that is not used for drinking purposes if conditions for dilution are 
otherwise favorable, but in most cases it should be first oxidized in some 
other way. 

If it is desired to effect a greater degree of purification than the 
mere removal of suspended solids, the tank effluent should be subjected 
to one of the following ' ' oxidizing ' ' processes. 

Trickling filters and contact beds are adapted in particular to large 
installations where the services of an expert are required both in the 
design and operation. 

A special design suitable for use by from 6 to 120 individuals has 
been recently prepared by the United States Public Health Service, 
consisting of a grease trap, Imhoff tank, screen, tipping distributer, a 
lath filter, from Sy 2 to 6 feet deep having a volume of 8 cubic feet per 
capita and a secondary Imhoff tank. The whole device is made of wood 
and for 10 persons is only 13 feet by 5 feet 10 inches by 11 feet 
inches high. ' ' The degree of purification effected is sufficient for all 
purposes except where the discharge is directly into a water supply. In 
such a case chemical disinfection of the effluent is recommended in addi- 
tion. * * * The plant will operate without a nuisance, and, with a 
monthly inspection and semiannual or annual removal of sludge from 
the tanks, will operate continuously without further attention." (Re- 
print Xo. 504, Public Health Reports, 1919.) Such a plant should be 
protected from the weather, particularly in cold climates, and its life 
would be much shorter than if built of masonry. 

Another compact device consists of a tank followed by a fine copper 
screen or sand filter and then a filter of gravel or pebbles through 
which air is permitted to rise. 

Surface irrigation, unless under expert supervision, is not recom- 
mended, as offering too many opportunities for the production of odors 
and mosquitoes and for infection through flies. 

Subsurface irrigation by lines of open joint tile laid from 8 to 15 
inches below the surface may be the best method to employ provided 
the soil is not water-soaked or too impervious. The former difficulty is 
sometimes overcome by embedding the tile in a light fill of sandy soil. 
The irrigated area should be at least loO feet from any habitation. 

To prevent clogging the soil the sewage should pass through a grease 
trap at the house and to promote aeration in the soil it should be de- 
livered intermittently from 3 to 6 times a day (somewhat less if the 
soil is dense) by a siphon contained in a dosing chamber after leaving 



266 HYGIENE: DENTAL AND GENERAL 

the tank. This device may usually be omitted, however, where the house 
is only occupied during the summer. 

The tile should generally be 3 or 4 inches in diameter, laid with a 
piece of tar paper over the joint and with a gradient of from 2 to 6 
inches per 100 feet. The length depends upon the volume of sewage 
and the character of the soil, varying from 50 to 100 feet for an ordinary 
family. "Where more than 100 feet is required in all it is generally de- 
sirable to lay two or more lines of tile. The arrangement may vary 
with the topography but parallel lines should be more than 6, and pref- 
erably 10 feet apart. Unless the soil is quite open the irrigated area 
may best be operated in two units, dosed alternately. If the land is 
cropped this should be limited to grains, fodder crops and fruit trees. 

Owing to the difficulty of securing uniform distribution of the sewage 
by reason of the variations in the permeability of subsoil or improper 
gradients or joints in the lines of tile, and, further, owing to the difficulty 
in securing any effective drainage when the soil is saturated by storms, 
there is a measure of uncertainty in obtaining uniformly satisfactory 
results with this method of disposal; so that, unless the conditions are 
favorable and other satisfactory methods are not feasible, subsurface 
irrigation is not recommended. 

Sand filtration may be used for tank effluents where more than 25 per- 
sons are served and where the land is suitable. For this number of 
persons an area of about 1,500 square feet of bed is required. The 
filters require careful design and maintenance. Cropping is usually 
undesirable. Dosing should be intermittent and applied in rotation to 
a depth of from 3 to 6 inches to two or more beds. In winter the 
beds should be furrowed to prevent freezing. 

Sludge disposal. Sludge from tanks should be dried on porous soil 
or on specially prepared beds. It should be placed in layers of from 
4 to 10 inches in thickness — the thinner the better — until sufficiently 
dry to be spaded, when it can be buried, plowed under or used as fer- 
tilizer. Well digested Imhoff sludge may be used to fill in land. 
Sludge from secondary tanks,* being difficult to dewater, should be 
placed on specially prepared beds to a depth of from 2 to 4 inches. 

Otherwise, sludge may be drawn off into furrows and covered over. 

Fly breeding may be prevented by applying a solution of borax as 
in the case of nightsoil. 

To prevent odor, sludge may be covered with a thin layer of car- 
bonate of lime or "land plaster." 

The soalcage pit is useful for the disposal of kitchen slops and urine 
where the water-carriage system is' not available. 



Those taking the effluent from filters. 



WASTE DISPOSAL 267 

Slcvps may be spread over the surface of the ground in out-of-the-way 
locations provided the soil is porous and no standing water remains. 
Otherwise, a pit about three feet deep filled with broken stone, gravel, 
sand or clinkers may be prepared to which the slop water is discharged 
after the removal of coarse solids by a strainer and the grease by a trap. 
The bed may be covered with a foot or so of earth to bring the top to 
the ground level and prevent access to insects. 

For large volumes a tank and dosing siphon may be employed with 
advantage, and a system of subsoil tile substituted for the soakage pit. 

Where many persons are to be provided for, as in schools, hotels 
and in the latrines of army camps, urinals should be installed, but for 
private dwellings a hinged seat that can be lifted is a simpler and 
suitable arrangement. 

Urinals should be flushed with at least a gallon of water daily, and 
it is desirable that they be automatically fed with cresol or some other 
deodorant. The liquid can then be led to a soakage pit similar to 
that provided for slops. 

Another plan suitable for camps is to build one or more vertical 
funnels into the stone filling of the pit to serve as urinals. 

Such a pit may be about 3 feet to 6 feet square with 24 inches depth 
of broken stone or other pervious material on the bottom, depending 
on the material and the number of persons served. Large installations 
should consist of several such units. 

If preferred, a larger unit, 4 feet by 12 feet by 4 feet deep, adequate 
for 100 men, may be substituted for the one described. 

For emergency use a cone of 6-mesh wire 18 inches in diameter at 
the upper end, 24 inches long and filled with sawdust will serve with- 
out a pit for G or 7 men. 

Disposal of Garbage 

Garbage should be collected without admixture of ashes or other 
material in metal cans having tight covers, with one always available 
-while the others are being emptied. The cans should be scalded with 
hot water after emptying. 

Garbage is sometimes used to fill in waste land, but foi obvious 
reasons this is not to be approved. 

Garbage from . households may be satisfactorily disposed of by 
burial following the rides laid down for nightsoil. Sometimes it is 
plowed under as a fertilizer, but although it has some value in this 
respect, the probability of odors ordinarily excludes this as a sanitary 
procedure. Where odors from garbage do occur the latter should be 
sprinkled with quicklime. 



268 



HYGIENE : DENTAL AND GENERAL 



If without too large a proportion of moist vegetable matter a mod- 
erate amount can be safely consumed in the kitchen range, although 
at the risk of odor; while if the quantity is sufficient, as in a con- 
struction camp or a military cantonment, a small but well designed in- 
cinerator will eliminate much of this objection. 

Burial in summer and incineration in winter, when the ground is 
frozen and the garbage is less moist, will often be found advisable. 

For camps the "Woodruff Pit" has been found a satisfactory de- 
vice. This consists of an excavation in the ground from 10 to 13 








Fig. 44. — Outdoor incinerator (Arnold type) . (Gardner.) 



feet in diameter and 4 feet deep, lined with fieldstone. A conical pile 
of stone or a cone of brick with open joints is built in the center 
around a chimney of two or more lengths of sewer or stovepipe. Gar- 
bage and nightsoil placed on a fire built in the pit will usually be 
readily consumed; but if, on account of wet weather or very moist 
garbage, a more rapid combustion is desired, this may be had by pour- 
ing on a little kerosene oil. Care should be taken to prevent dissemi- 
nation of papers, etc., by the wind. 



WASTE DISPOSAL 269 

Another arrangement consists of a pit 5 by 2% feet in plan with 
the bottom sloping from a depth of 6 inches at one end to 12 inhces 
at the other. The trench is filled with fieldstone or, if these are not 
available, with tin cans, the excavated material is banked up on the 
sides and a fire built on top. After the stones are thoroughly heated 
any liquid wastes are poured in the trench at the shallow end of the 
pit, in which they are evaporated, and the solid material placed on top 
where it first dries out and then burns, up. 

A certain amount of odor will probably be inevitable with incinera- 
tion, but with competent operation this need not be serious in the case 
of camps. 

As garbage contains a considerable amount of grease which can be 
recovered by percolation with some solvent, leaving a tankage with some 
value as a fertilizer base, this may prove a wise method of disposal 
where collection can be made from a considerable population; but as 
the plant required is rather elaborate, this process can seldom be availed 
of except for large cities. The demand for grease and fertilizer has 
increased so during the war, however, their recovery should be considered 
in connection with army camps and cantonments. 

Probably the most economical method for the farmer and for towns 
of moderate size is in feeding to hogs, due care being taken to maintain 
cleanly conditions about the pens. The garbage should not be kept more 
than 48 hours in any case before feeding. On account of the possible 
nuisance from smells and flies the pens should be located, if possible, 
at least a quarter of a mile from dwellings. 

Disposal of Manure 

The manure pile is a most prolific source of flies, which find in it a 
favorable environment for breeding. As it takes about two weeks for 
the larvae to develop, these should always be destroyed if the manure is 
to be kept for a longer period except in cold weather. 

Fifty horses will produce a cartload of manure a day. Fly breeding 
may be prevented by an application of borax, using not over one pound 
to 16 cubic feet of manure if the latter is to be used as a fertilizer, but 
a better i>lan i s to sprinkle with a solution of two pounds of copperas 
per gallon of water, or with a solution of hellebore mixed in the pro- 
portion of one pound to 20 gallons of water and applied at the rate of a 
gallon of the solution to each cubic foot of manure. By consolidating 
the exposed surface of the manure by battening with a spade it will pre- 
vent to a considerable extent the breeding of flies. The heat generated 
just below the surface by decomposition is then such that the larvae are 
largely destroyed. 



270 HYGIENE : DENTAL AND GENERAL 

The most natural use for manure is as a fertilizer, but where this 
is impracticable it may be piled in windrows about two feet high, sat- 
urated with oil and burned. 

Of the safeguards against disease in our rural communities those re- 
lating to the protection of water supplies and to the transfer of disease 
germs by flies are by far the most important; so that, whatever method 
of disposal is adapted to a given situation it should be such that no 
cxcretal matter can find its way, either by percolation through the soil 
or by surface wash during storms, to wells or streams used for drinking 
purposes, and that all such excretal matter shall oe so protected by 
screening or otherwise that flies cannot find access thereto. 

In this connection it may be well to point out that when the polluting 
material lies at a higher elevation than the water surface in a neigh- 
boring well there is always the tendency of contamination of the well; 
but where the source of pollution lies permanently at a lower elevation 
contamination of the well will not occur. 

During the preparation of this report the committee has addressed 
inquiries regarding the subject treated to the health authority of each 
state as well as to others and has received in return a large number 
of bulletins, reports and prints containing information of great value 
that has been freely drawn upon and for which the committee desires 
to express its hearty appreciation and thanks. 

Eespectfully submitted, 

Kenneth Allen, Chairman. 
Frank A. Barbour, 
George S. Webster, 
T. Chalkley Hatton, 
Langdon Pearse, 
Committee on Sewerage and Sewage Disposal, Sanitary Section Ameri- 
can Public Health Association. 

Bibliography- 
Manure Disposal as a Factor in the Control of Parasitic Diseases of 

Live Stock. Jour. Am. Veterinary Medical Assn., Vol. LI, 1917. 
Kules and Regulations, Arkansas State Board Health, Pertaining to 

Disposal of Human Excreta and Disposal of Dead Animals. Aug., 

1913. 
Sewage Disposal for Isolated Residences. Bui. No. 8, California State 

Board Health, 1918. 
Act to Regulate the Disposal of Certain Refuse. Approved Jan. '2.1, 

1898. Rep. Health Officer, District of Columbia. 
School Sanitation. Florida Health Notes. Florida State Board Health, 

Jan., 1918. Public Health Legislation, Florida State Board Health, 

July, 1915. • 



WASTE DISPOSAL 271 

Disposal of Sewage for Country Houses, Small Institutions and Country 
Clubs. Illinois Health News, Aug., 1916. 

Sanitary Privies. Bureau of Sanitary Engineering. Illinois Health 
News, May, 1917. 

Eules and Begulations, Iowa State Board Health. Supplement to Iowa 
Health Bulletin, 1917. 

Methods of Sanitary Disposal of Sewage without Sewers. Health Cir- 
cular Xo. 2, Indiana State Board Health, 1915. 

Amendments to the Sanitary Code of Louisiana from 1911 to Dec. 18, 
1915. 

Sanitary Privy for Eural Districts. Louisiana State Board Health, June, 
1918. 

Sewage Disposal for Country Houses. Quarterly Bui. Louisiana State 
Board Health, May, 1913. 

Hygiene of Eural, Suburban and Summer Homes. Circular Xo. 100, 
Maine State Board Health. 

A Sanitary Privy. Maryland State Board Health. 

Typhoid Fever. How It May Be Avoided. Maryland State Board 
Health. 

The Sanitary Privy. Eng'g Bui. Xo. 8, Michigan State Board Health. 
Feb., 1918. 

Sewage Disposal for Single Houses and Small Institutions. Eng'g Bui. 
Xo. 2, Michigan State Board Health, Sept., 1916. 

The Chemical Closet, Eng'g Bui. Xo. 5, Michigan State Board Health, 
Oct., 1916. 

State Health Laws and Regulations, Minnesota State Board Health, July 
16, 1917. 

Water and Sewerage Systems for Public School Buildings. Minnesota 
State Board Health, Jan., 1917. 

The Sanitary Privy. Minnesota State Board Health, May, 1916. 

The Disposal of Human Excreta and Sewage of the Country House. Xew 
York State Department Health. 

Sanitary Privies and How to Build Them. Spec. Bui. Xo. 7, North Car- 
olina State Board Health, Mar., 1917. 

Sewage Disposal for Country Schools in Ohio. Ohio Public Health Jour- 
nal, Aug., 1916. 

Sewage Disposal for Residences. Ohio Public Health Journal, Sept. -Oct., 
1916. 

Public Health Laws of Oklahoma. Spec. Bui. Xo. 101, Oklahoma De- 
partment Public Health, Nov., 1917. 

Sewage Disposal. Circular Xo. 39, Dept. Provincial Sec'y of Ontario. 
Thirty-fourth Eep. Provincial Board of Health of Ontario. 

The Dangerous Unsanitary Dry Closet. Texas Council of Defence. 



272 HYGIENE: DENTAL AND GENERAL 

Home Sanitation. Bui. Texas State Board Health. 

Standards of the Department of Health and Sanitation. Emergency 
Fleet Corporation. 1918. 

Transmission of Disease by Flies. Supplement No. 9, U. S. Public 
Health Reports, 1916. 

Flies as Carriers of Lamblia Spores. Eeprint 154, Public Health Re- 
ports, 1913. 

Soil Pollution. Reprint 127, Public Health Reports, 1913. 

Sewage Disinfection. Reprint 247, Public Health Reports, 1915. 

Information of the Current Prevalence of Disease. Public Health 
Reports, 1918. 

Chemical Closets. Reprint 404, Public Health Reports, 1917. 

New Design for a Sanitary Pail, Reprint 138, Public Health Reports, 
1913. 

The Sanitary Privy. U. S. Public Health Bui. No. 37, 1914. 

Safe Disposal of Human Excreta at Unsewered Homes. U. S. Public 
Health Bui. No. 68, 1915. 

A Sanitary Privy for Unsewered Towns and Villages. IT. S. Public 
Health Bui. No. 89, 1917. 

Fly Traps and their Operation. Farmers' Bui. No. 734, II. S. Dept. 
Agric, 1916. 

The Sanitary Privy. Virginia Health Bui., Dec. 15, 1912. 

The Pit Privy. Virginia Health Bui., Aug. 15, 1915. 

Rules and Regulations for Protection of Public Health. Virginia Pub- 
lic Health Bui., July, 1916. 

Sanitary P'rotection of the Home. Virginia Public Health Bui., March, 
1917. 

Rural Sanitation. Washington State Board of Health, 1916. 

School Privies. Bui. Wisconsin State Board Health, Jan.-M.ar., 1918. 

Residential Sewage Disposal. Bui. Wisconsin State Board Health, Oet.- 
Dec, 1917. 

Proceedings Third Biennial Conference of Health Officers of Wisconsin. 
1916. 

Code for Rural School Privies. Wisconsin State Board Health, 1918. 

Twenty-sixth Report State Board Health of Wisconsin. 

Sanitation of Rural Workmen 's Areas. Reprint 487, U. S. Public Health 
Reports, 1918. 

Rockefeller Foundation. International Health Board,, 4th Annual Re- 
port, Dec. 31, 1917. 

Sewage Treatment for Village and Rural Homes. Bui. 41, Engineering 
Experiment Station, Iowa State College of Agriculture. 

Rural Home Sanitation. Pub. No. 2, Texas State Board Health. 



WASTE DISPOSAL 273 

The Treatment of Sewage from Single Houses and Small Communities. 

Eeprint 504, Public Health Reports, U. S. Public Health Service. 
Camp Sanitation. Jour. Franklin Inst., June, 1918. 
Field Sanitation. C. G-. Moore and E. A. Cooper. 
Orders Relative to the Operation and Maintenance of Water and Sewage 

Works at Army Camps and Cantonments. Construction Division, 

U. S. A. 
Sanitation in War. Maj. P. S. Lelean. 
Prevention of Disease and Care of the Sick. U. S. Public Health Service. 



CHAPTER XIV 

SCHOOL HYGIENE 

The Problem. — The duties of organized government in 
School Hygiene are extensive and important. The state by 
its excellent compulsory school attendance law places almost 
a third of our total population in this "factory" for the de- 
velopment of the mind. Dr. Osier has said that most of the 
diseases which cause death in middle life are developed from 
conditions begun in childhood. America has been behind the 
European countries in developing the subject of School Hy- 
giene but the examination of ten million of our population 
in the selective draft brought home forcibly to the American 
people the fact that one-third to one-half of our young men 
are unfit for full military service because of physical defects 
many of which are correctable. We have begun to face the 
problem of properly caring for our school children in a serious 
and right-minded fashion realizing the vast amount of work 
which lies before us. 

The following discussion of this broad and complex sub- 
ject is intended to give only the outline and general nature 
of the problem with special emphasis upon those phases of the 
work in which the dentist is likely to take part. Nor shall 
we attempt to define the relative responsibilities of the edu- 
cational and health agencies of the government in this field. 
Obviously there is both an educational and a health aspect to 
the problem. The personnel of both departments is necessary 
and a division of the details of administration must, for the 
present at least, frequently depend upon local conditions. 
The question of who does the work is not so important as that 
the work is done and done properly. 

274 



SCHOOL HYGIENE 275 

Special Groups of Defectives. — School authorities keenly 
realize the difficulties in educational progress caused by the 
special physical, mental and temperamental disabilities from 
which certain children suffer. These children have defects 
which make it desirable and in some cases imperative, both 
for their own good and in justice to the other pupils, that 
their education be conducted in special classes apart from the 
public school. Such defectives have been divided into the 
following eight classes: (Crowley's Hygiene of School Life.) 

1. Nervous children. 

2. Backward children, consisting of two main subdivisions : 

(a) Dull children whose backwardness is due to some accidental 

cause. 

(b) Dull children with inherent diminished capacity for book 

learning-. 

3. Mentally defective children : 

(a) Feeble-minded. 

(b) Imbeciles and idiots. 

4. Children with defective vision or blindness. 

5. Children with defective hearing, deafness or deaf mutism. 

6. Physically defective children, including cripples. 

7. Epileptic children. 

8. Children suffering from a combination of physical and mental 

defects, e. g., the blind idiot, the feeble-minded deaf child. 

Obviously, the education of these children is a health prob- 
lem as well as an educational problem, and medical service 
is necessary in handling the problem of special classes. How- 
ever, we must leave these specialized problems and confine 
our attention to the hygiene of the public schools. 

The Scope of School Hygiene. — The activities included in 
school hygiene naturally fall into three groups : 

1. Health supervision or the care of the physical well-being 

of the child. 

2. Instruction in Hygiene or the education of the child in 

matters of health. 

3. Proper sanitation of school buildings and grounds, the 

preparation of proper conditions for study, and the 
conduct of school work under hygienic conditions. 



276 HYGIENE; DENTAL AND GENERAL 

1. HEALTH CONTROL 

The following table presents the scope of the work of the 
first group in more detail: 

1. Medical or health supervision. 

(1) Regular, periodical, physical examination of children. 

(2) Correcting physical defects, eye, ear, nose, throat, 
posture and nutrition. 

(3) Checking incipient maladies. 

(4) Correcting unhygienic habits of living with follow- 
up work at home. 

(5) Dental examination, prophylaxis and repair. 

(a) Cleaning teeth. 

(b) Filling six year molars. 

(c) Teaching oral prophylaxis. 

(6) Prevention of Communicable Diseases. 

Personnel. — Four types of specially trained people are 
necessary for the administration of the medical side of school 
inspection, the physician, the school nurse, the dentist and the 
dental hygienist. 

The physician must be a capable diagnostician with a fond- 
ness for the type of work and with a public health point of 
view. 

The school nurse has a variety of duties in assisting the 
doctor in the routine of medical inspection, visiting homes and 
interviewing parents, visiting schools and examining children 
for infectious diseases, assisting in treatment at the school 
clinic and occasionally giving instruction in hygiene to the 
pupils. It is therefore, highly important that she have the 
ability of making the proper contact with pupils and parents, 
as well as the ability to detect communicable disease and assist 
the physician. If she is to instruct in the school she should 
know something about teaching as well as nursing because 
they are two distinct professions. It no more follows that a 
nurse can teach than that a teacher can nurse. The nurse is 



SCHOOL HYGIENE 277 

the point of contact between the. family, the child and the 
school medical authorities and upon her common sense and 
practical work often depends the success of the plan. Her 
failure to secure the cooperation of the parents in having the 
bodily defects of the child corrected and in maintaining bet- 
ter home conditions means a failure to secure a practical re- 
sult of health improvement. The woman who can appreciate 
the problems of the homes she visits adds something to the 
value of her work which detailed. scientific knowledge cannot 
supply. 

The work of the dentist may be orthodontia, repair work 
or prophylaxis but it is work at the chair and not widely 
different from routine practice. 

The dental hygienlst stands to the dentist in much the same 
relation as does the nurse to the physician. She must work 
with the children and perhaps in some instances with the 
parents. She examines the teeth and fills out a record card, 
prepares the patient for the dentist and cleans the teeth. 

Physical Examination. — Dr. Crowley, of England, who has 
examined many hundred children gives the following figures 
indicating the proportion of children having diseases and com- 
mon defects requiring treatment among elementary school 
children : 

Defects of vision 10%; defects of hearing 5%; ear diseases 3%; 
marked decay of the teeth 50%; (some decay 80-90%); Tuberculosis 
2%; heart disease 1%; malnutrition 10%; ringworm 1%. 

The physical examination of the child, however, is even 
broader than this list of defects and Should include a study 
of cleanliness, nutrition, height and weight, heredity and en- 
vironment, and an examination for squint, external eye dis- 
ease, defective hearing, adenoids, ear discharges, enlarged 
glands, defective teeth, acute rheumatism, chorea, heart dis- 
ease, lung disease, bronchitis, venereal disease, rickets, ane- 
mia, headache, diseases of the skin, and deformities. The fol- 
lowing card is one devised by the U. S. Public Health Service 
for recording the results of physical examination. 



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a 


- 



x :- z y g 



280 HYGIENE : DENTAL AND GENERAL 

This form is more elaborate than many communities are in 
a position to use. In any case the record card should always 
be of suitable size for filing and should be made a permanent 
record so that the health progress of the child may be ascer- 
tained at any time. 

Treatment. — The defects having been discovered, treat- 
ment must be secured. A blank somewhat after the follow- 
ing form may be sent to the parent. 



Office Medical Inspector of Schools 



Parent or Guardian Address 

A recent physical inspection of 

Name of child 

attending the indicates the f ollowing 

Name of school 
abnormal conditions: 

You are advised to take , to your 

Name of child 
family physician, dentist, oculist, or to a dispensary for advice 
and treatment. 



Medical Inspector, 



The examination should be made at the school and the clin- 
ical work may be done either at the school or at some building 
of the Health Department. This work requires special con- 
veniences and equipment. The chart on p. 281 shows the 
floor plan and arrangement of the medical inspector's room 
in general use in New York City. 

These quarters should be centrally located, preferably on 
the ground floor, and should have the essentials of a waiting 
room, proper lighting, an electrically lighted chart and dis- 
tance of 20 or at least 15 feet for eye examination, a lava- 
tory and table with the necessary filing cabinets for records. 
The diagram shows a convenient arrangement by which the 
waiting room space may be used in eye examinations so that a 
room 12 by 20 feet is made sufficient. In cases where the 
room is not in constant use it may be used on alternate days 



SCHOOL HYGIENE 



281 



as a clinic. In this case the room should be somewhat larger 
and might contain as a complete equipment: a desk, ward- 
robe, medicine cabinet, two chairs, couch, lavatory, scales 
with measuring rod, electrically lighted vision chart, portable 
screen and a filing cabinet with the medical and surgical sup- 
plies in most common use such as cotton, gauze, bandages 
(1 and 2 inch), boracic acid, green soap, collodion, tincture of 




Fig. 45. — Floor plan and arrangement of medical inspector's room generally fol- 
lowed in New York City. By the arrangements indicated, the width of the waiting 
room may be used in eye examinations and a space 12 by 20 feet is sufficient for 
both waiting room and examining room. (After Berkowitz.) 

iodine, sulphur ointment, white precipitate ointment, vaseline, 
peroxide, lysol, aromatic spirits of ammonia, hand scrub, 
tongue depressors, toothpicks, argyrol, cocaine, bichloride of 
mercury, atropine, alloy, bluestone, yellow oxide of mercury, 
and nitrate of silver. 

Administration. — Perhaps the best way to describe the med- 
ical activities in school hygiene is to cite the example of a city 
which has developed a good system of medical inspection. The 



282 HYGIENE: DENTAL AND GENERAL 

city of Detroit, Michigan, which has a population of 900,000 
and a school population of 130,000, has perfected a division 
of medical school inspection under the Department of Health. 
The present activities of this division are described in the 
monthly bulletin of the health department for September, 
1919, by Henry F. Vaughan, D.P.H., health officer for the 
city. 

This department has been in operation for ten years and 
records show that communicable diseases among school chil- 
dren are decreasing from year to year. The department has 
established a routine procedure for the prompt detection of in- 
fectious diseases, for exclusion of cases from school under 
proper quarantine and treatment and for the prompt return 
of the pupils to school after the quarantine is lifted. School 
inspection is done under the medical director who has in 
charge 50 medical inspectors. These inspectors visit from 
three to five schools every school day working from 9.00 a.m. 
to noon. Standing orders have been issued to all teachers by 
the Board of Education through the agency of the Department 
of Health to send promptly to the examining room all pupils 
coming under the following heads : ( 1 ) children who were ab- 
sent on the previous day, (2) children who have a skin erup- 
tion or rash, (3) children having sore throat or fever, (4) 
children having persistent cough or sore throat. The teach- 
ers are also instructed to report remedial defects among chil- 
dren in her room such as eye and ear defects, tonsils, enlarged 
glands, deformities, etc. This places a burden on the teacher 
which normal school girls are not well equipped to bear as 
they are trained at present. Either the teacher should have 
more training in the detection of signs of infectious disease 
and bodily defects or the nurse should be able to do this work 
in the school room. 

In Detroit the nurse arrives at the school in advance of the 
medical inspector, and does the nonmedical work, being able 
to eliminate some of the pupils sent down to her for possible 



SCHOOL HYGIENE 283 

exclusion from school. All children having returned to 
school after an absence are questioned and on the average two 
out of every ten questioned are excluded. 

For instance, Johnny tells the nurse that he was absent because he 
had a sore throat. In answer to further questions Johnny informs the 
nurse that his mother and two other members of the family are suffer- 
ing from sore throat, The nurse takes' a culture and Johnny is sent 
home. Later in the day she visits Johnny's home for the purpose of 
making a more extensive survey. If her suspicions are aroused she 
telephones to the Department of Health and a diagnostician is sent 
to the house. If a true case is found immediate measures are taken 
to quarantine the family. 

In this city the nurses are unable to do much work in the 
schoolroom because they are not yet supplied in sufficient 
numbers, there being only one nurse to 9000 pupils. Dr. 
Vaughan believes that the ideal proportion is one nurse for 
1500 to 3000 pupils. 

The children are arranged in groups for the attention of 
the medical inspector, so that he finds them in the examining 
room each with a card properly made out. The children with 
sore throats are in one group, those with skin rashes in an- 
other, etc. The medical inspector takes up the work of the 
nurse making a diagnosis and giving to the principal a list of 
the children to be sent home. It is Dr. Vaughan 's practice 
to recognize the presence of two cases of a communicable dis- 
ease in the same school in one week as an incipient epidemic, 
in which case the inspector makes an examination or takes a 
culture of every child in the school. During the school season 
a ph} r sical examination is made of every school child so that 
defects which are overlooked by the teacher are picked up 
at that time. All schools, public and parochial, are under 
the Department of Health Medical Inspectors and an impor- 
tant activity of the general physical examination is the placing 
of afflicted children in special schools of which the Board of 
Education now has four types including a school for the blind, 
one for crippled children, a school for deaf children and four 
open aii- schools. 



284 



HYGIENE: DENTAL AND GENERAL 



^-■M 


BMPBT. " , ^P ,l,, g 


Hp*F|p 


31 1 


p 


MSpP#i 




7 It 




lug. 46. — The effect of treatment for adenoids upon the general appearance of 
three children. The upper picture was taken before treatment; the lower, after 
treatment. 



Defective Vision. — Special attention must be given to the 
conservation of vision and the correction of visual defects, for 
school life places a heavy strain upon the eyes. The accom- 
panying diagram shows the physical basis of far-sightedness 



SCHOOL- HYGIENE 



285 



and near-sightedness as compared with normal sight. In nor- 
mal sight (emmetropia) the image is sharply focused on the 
retina. In far sight (hypermetropia) the eye ball is too shal- 
low and the perfect focus of the image would take place be- 




Fi g 47.— Errors in refraction: E shows the formation of the image on the ret- 
ina in the normal or emmetropic eye; H shows the condition in long-sight, or hy- 
permetropia, where the eyeball is too short; M shows the condition in short-sight, 
or myopia, where the eyeball is too long.' (Pearce-Macleod.) 

hind the retina. There is therefore a blurred image and in- 
distinct vision. Hypermetropia is more commonly found in 
young children and many of these cases tend to correct them- 
selves. However, all cases where eye strain is involved should 
receive treatment. 

In near sight (myopia) the eye ball is too deep and the 
image is focused in front of the retina. Myopia is a more 
common defect among older children ; it is a more serious con- 
dition and should not remain untreated. The amount of my- 
opia increases where there is less occasion to use distant vision. 



286 HYGIENE : DENTAL AND GENERAL 

City children have been shown to have more near-sightedness 
than country children. The schools themselves may be re- 
sponsible for some degree of deterioration of vision. This is 
especially true if the student holds his work too close to the 
eye. There are many factors which may induce near or 
strained vision such as insufficient light, light from the wrong 
direction, a strong light in front of the eyes, faulty position 
of the pupil in relation to the blackboard, faulty illumination 
of the blackboard producing shiny surfaces, faulty desks and 
seats leading to bad postures and bending of the head, and the 
condition of the child 's general health. 

Astigmatism is a defect of a different type. In some cases 
it is of little consequence if no symptoms are produced by it. 
On the other hand, it may be a very serious defect which of 
itself is the cause of "eyestrain" with the accompanying head- 
aches and poor health. This is a condition which calls for 
accurate and careful correction. There are different kinds of 
astigmatism, according as the eye is, in the vertical and hor- 
izontal meridians respectively, hypermetropic, or myopic. In 
what is known as mixed astigmatism, there is hypermetropia 
in one meridian and myopia in the other. 

The Dental Care of School Children. — No more conclusive 
proof of the importance of the dental care of school children 
can be cited than to describe the experience of cities where 
school hygiene has been practiced extensively. The work at 
Bridgeport, Conn., under Dr. Alfred E. Fones has been more 
extensive and elaborate than that in any other American city. 
It is not out of place, therefore, to consider in some detail the 
work which Bridgeport has carried out. The total number 
of children examined and treated in the first and second 
grades the first year was 6,768. On the first examination less 
than ten per cent were brushing their teeth daily. About 
thirty per cent claimed that they brushed their teeth occasion- 
ally, while sixty per cent were frank enough to state that they 
did not use a toothbrush. Ten per cent of the children were 



SCHOOL HYGIENE 287 

found to have fistulas on the gums, showing the outlets of ab- 
scesses from the roots of decayed teeth, and they averaged over 
seven cavities per child. "It was shocking," writes Dr. 
Fones, ' ' to find the mouths of these children five to seven years 
of age in this deplorable condition, and it was appalling to 
contemplate the conditions that w^ould exist in these mouths 
as the children grew up. It presented very interesting ma- 
terial to work with. ' ' The dentist can draw his own picture 
of the evil results in the oral cavity and in the system gener- 
ally when these defects remain uncorrected. 

Dr. Fones made the following statement before the National 
Dental Association in 1917. (Mouth Hygiene for U. S. 
Soldiers, National Dental Association, 21st Annual Session, 
New York, October, 1917.) 

We have tried to work out this plan in Bridgeport, and after three 
years we find that our educational and preventive dental clinic is the most 
important part of our school and health systems. Under the plan of 
this clinic every child undergoes an examination of his mouth and re- 
ceives a prophylactic treatment of his teeth, accepting it as much a 
part of the school curriculum as his geography lesson. Every child is 
taught a method of brushing his teeth and is educated in the care of 
his mouth just as he is taught physiology or calisthenics. In this way 
the municipality accepts one-half the responsibility of aiding and edu- 
cating the children in the prevention of dental decay, while the home 
care of the mouth and proper feeding is assumed by the child and his 
parent. 

The work of the clinic is divided into four distinct parts. First, the 
actual cleaning, polishing, and examination of the children's teeth in 
schools. Second, the toothbrush drills and class room talks. Third, 
stereopticon lectures for the education of children in the higher grades. 
Fourth, educational work in "the home carried on by special literature to 
gain the cooperation of the parents. It may be well at this point to 
make clear to those outside the dental profession what a prophylactic 
tieatment really is. It consists mainly in the thorough cleaning, by 
means of orange wood sticks in hand polishers, of every surface of every 
tooth. This means the removal of all stains and accretions on the teeth 
and especially of the sticky, mucilaginous films known as bacterial 
placques, which are the initial stage of all dental decay. The importance 
of removing these placques can thus be readily understood. This work 
of prevention of dental decay is essentially ;i woman's work, and to the 



288 HYGIENE: DENTAL AND GENERAL 

dental hygienist it opens up paths of usefulness and activity in helping 
humanity in masses. 

In 1913-14 we trained the first class of dental hygienists in Bridgeport, 
and two of these women were selected as dental supervisors when our 
clinic started in the fall of 1914. We had received $5,000 to carry on a 
demonstrating preventive clinic for the children of the first two grades 
of our schools, and our corps consisted of eight dental hygienists and two 
supervisors. In but one year our city officials were so impressed with 
the results of our work that the appropriation was doubled, the corps 
enlarged, and a woman dentist added, and now, the fourth year of our 
clinic, we have a corps of twenty dental hygienists, two supervisors, and 
two women dentists, and an appropriation of $21,529. The money is 
appropriated through the board of health and the clinic is conducted by 
a subcommittee of this board. 

Time will not permit giving a detailed report of our clinic from its 
start in 1914, but it may be said that the system now employed is very 
similar to that used originally. 

The dental supervisors oversee and direct the work of the dental 
hygienists, give classroom talks, toothbrush drills, stereopticon lec- 
tures, and attend to the distribution of literature to children and sup- 
plies to the hygienists, and arrange for the moving and location of 
hygienists in each school. 

The work of the dental hygienists consists in making the examination 
and records of the teeth, giving the prophylactic treatments and in- 
structions in the home care of the mouth. 

When the equipment is placed the hygienist begins work for the 
children of the first grade and takes each grade in succession through 
the fifth. The charts are ' made of each child 's mouth, one for the 
parent and one which is a permanent record for the files, showing the 
conditions found in the mouth for a period of five years. 

Aside from the actual cleaning of the children's teeth, the work 
of the supervisors with toothbrush drills is considered very important, 
and every effort is made to present this phase of mouth hygiene to 
the children in a way that will be educational and interesting. It has 
been quite a problem to secure a good brush that can be sold for five 
cents, and up to the. present time nothing better has offered than fac- 
tory seconds of a good make of brush. 

On the day preceding a toothbrush drill a notice is sent to the parent 
requesting that the child be allowed to bring his tooth brush to school, 
and that it be securely wrapped in clean paper. Announcement is made 
in the classrooms that any child may purchase a new toothbrush for 
five cents. The drill proper is given with the children seated, while 
the assistants pass up and down the aisles helping the children to hold 



SCHOOL HYGIEXE 289 

the brushes . correctly ancL to .make -the right movements. There are 
four positions for holding the brush and two movements in each drill. 
The children brush to count in a stereotyped form, it being intended 
to teach merely the correct form of orushing and not meant for the 
actual cleaning of the teeth which would require running water and 
dentifrice. A second talk is given up to the care of the brush and the 
necessity of hanging it in a clean place. The children repeat the drill 
standing, and the brushes are wrapped in clean waxed paper to be 
taken home. 

It is hardly possible to estimate the educational value of the tooth- 
brush drill in the classroom. It is accepted by the children as a part 
of the curriculum, and therefore something to be learned and remem- 
bered. The teachers have aided in many ways to assist the children in 
forming the habit of daily brushing. 

When the children of the first and second grades receive their first 
treatment, it is frequently found that while many of the deciduous 
teeth are decayed, the few permanent teeth erupted at that age are 
sound, with the exception of the six-year molars. The very first small 
cavities are just appearing in these teeth, and we believe that the small 
children entering the prophylactic system should all start on the same 
basis, that is with sound permanent teeth. We have two women den- 
tists who work with the hygienists in our schools and confine their 
efforts to the filling of the first permanent molar teeth. We term this 
preventive dentistry also, as the effort is made to thus prevent the de- 
velopment of large cavities in these, the most important teeth of the 
denture. 

Five years ago Dr. Fones in beginning his work in Bridge- 
port examined the mouths of the children. of the fifth grade. 
These children had never received any dental attention. In 
1919 he again examined the mouths of children of the fifth 
grade, this being the first class to have received dental care 
upon entering school. The beneficial results of his work are 
shown by comparative figures. There was a reduction of 
caries in the permanent teeth of the fifth graders amounting 
to 33.9 per cent. This reduction was due in the main to three 
activities, (1) cleaning the teeth, (2) filling the six-year mo- 
lars, and (3) teaching prophylaxis and the use of the tooth- 
brush. 



290 



HYGIENE: DENTAL AND GENERAL 




SCHOOL HYGIENE 291 

The following story of the experience of dental clinics in 
the city of Detroit is told in the September (1919) Bulletin 
of that city. 

Special dental clinics are maintained for school children at fifteen 
different locations in the city. The clinics are so situated that they 
will be conveniently near the greatest number of schools. The dental 
inspection work includes all the schools in the city, public and parochial. 
The children are sent to the clinics in squads at appointed hours for* 
necessary treatment. 

During the school year of 1918-19, the dental clinics accommodated 
73,245 children. Of this number, only 8,638 did not need dental atten- 
tion. The necessity for this inspection work is emphasized by the fig- 
ures in the report showing that 54,409 decayed teeth were found by the 
inspectors, the number of permanent molars lost being 9,046. Nine hun- 
dred and ninety-two children were found suffering from abscesses, 
painful and health-destroying,. Fifty children had palatal defects. 

The Department of Health is unable to reach all the school children, 
the inspection staff being limited to five dentists, and not all of them 
serving during the full school year. An attempt will be made by re- 
ducing the reparative work and increasing the prophylactic work, to 
take care of new schools this year. It has been the plan in New York 
City, where it is impossible to reach all the school children needing 
dental treatment, to select children from the age of school entrance up 
to about ten or twelve years. It is known that a child's mouth during 
this period is in a most transitional stage, and that work done then will 
have a great effect for good upon the future, or adult, development and 
condition of the mouth. 

Enthusiastic cooperation on the part of teachers and principals of 
schools has greatly assisted the inspectors in their work. The teachers, 
particularly in schools where dental educational propaganda has been 
conducted, say that they have noticed the effect upon the children, es- 
pecially in what may be termed the improved tone of the pupils' per- 
sonal hygiene. Care of the teeth is one of the first lessons in body 
cleanliness. 

The teachers and pupils assist the inspectors by collecting an ' 
helping to fill out the report cards. When a child is found in need of 
dental work, the Department of Health sends a card to the parents or 
guardian, reading as follows: 

''Your child needs dental attention. This is the time to have the 
small cavities filled to prevent future loss of teeth. If you have a 
regular family dentist, will you please take your child to have these 
cavities filled while most of them are yet small. If you have no regular 



292 HYGIENE: DENTAL AND GENERAL 

dentist and positively cannot afford to pay for the work needed for 
your child, you may have such work done without charge in one of the 
free dental clinics of the Department of Health. If you wish this done, 
please sign and return this card to the teacher immediately. ' ' 

"With the opening of the present school season, the Department of 
Health dental staff comprises fifteen dentists and five dental hygienists. 
Under a new state law, employment of dental hygienists for dental pro- 
phylactic work is permitted, but as yet the department has been unable 
to interest a sufficient number of qualified dental hygienists, because 
they are largely employed in eastern cities. 

The work done by the dentists in the clinics consists of filling, ex- 
traction and operative treatment, together with such lectures and in- 
structions as are necessary. In addition, 69 cases of orthodontia, 
where the teeth were so irregular and malformed that the patients 
would suffer serious physical impairment if not attended to, were cor- 
rected during the year, 1,444 treatments being given in all. 

A free dental clinic is maintained on .the third floor of the Depait- 
ment of Health building, 233 St. Antoine street. The quarters are 
rather small for the volume of work handled. Five chairs are in opera- 
tion, in addition to an x-ray room and orthodontia room. The little 
patients are obliged to wait in the hall for their turn in the dental 
chair. 

However, this clinic is popular during the twelve months in the year. 
In addition to caring for school children, the clinic does work for others 
who have applied for employment certificates, but who, because of their 
teeth, cannot pass the required physical examination. Adults wanting 
teeth extracted or treatment for the ' ' toothache ' ' are also given at- 
tention. 

WOEK OF SCHOOL DENTAL CLINICS 
1918-19 

New cases 16,270 

Revisits 22,765 

Total visits to clinics 39,035 

Prophylactic treatment 12,294 

Fillings 14,323 

Treatments 7,876 

Extractions — 

Deciduous 17,427 

Permanent 4,218 

Surgical cases 23 

Curetment 162 

X-rays taken 124 



SCHOOL HYGIENE 293 

It is found necessary for the physician or dentist in charge 
of medical and dental school supervision to show the results 
of his work in reports issued from time to time which will 
secure for him the further cooperation and financial support 
of the city. His records should be made and kept with this 
in view. We have already cited the reduction in dental caries 
at Bridgeport since the installation of the dental clinic. The 
Health Department at Bridgeport is also able to show the 
benefits of medical and dental work in the reduction of the 
percentage of retarded pupils as shown in the following table : 

PERCENTAGE OF RETARDED PUPILS 



Grade 


Sept., 1912 


Nov., 1918 


Drop in 
Retardation 


I 


16.5% 


8.1% 


51% 


II 


37. 


15.3 


58 


Ill 


53. 


24.7 


53 


IV 


59.5 


31.7 


47 


V 


61. 


33.1 


45 


VI 


54. 


30.4 


44 


VII 


39. 


19.3 


50 


VIII 


27. 

40% 


12.5 


54 


Average 


20.1% 


50% 



The cost of reeducation in Bridgeport in 1912 was 42 per 
cent of the entire budget, whereas in 1918 it was only 17 per 
cent. A careful examination of conditions showed that the 
only changes in school management which have taken place 
during this period which might account for the improvement 
in the number of promotions are, (1) an effective reorganiza- 
tion of the courses of study which took place in 1915 and (2) 
the establishment of dental services in 1912 with better medi- 
cal as well as dental supervision. A clear case is therefore 
made for the benefit of health improvement and a return on 
the investment can be measured by the saving in reeduca- 
tion costs. 



294 HYGIENE : DENTAL AND GENERAL 

The reduction in the amount of certain communicable dis- 
eases also can often be attributed to school medical adminis- 
tration. In presenting data of this sort the school doctor and 
particularly the school dentist must be very careful to claim 
only what saving can actually be shown to be due to his own 
work. For example the city just referred to would show a 
marked reduction in the amount of communicable diseases 
among school children which is probably due quite as much 
to the establishment of an efficient system of general health 
administration with the employment of an exceptionally well 
trained health officer, in the person of Dr. Walter H. Brown, 
as to the establishment of special activities in school hygiene. 
School health and municipal health react upon each other. 

2. TEACHING HYGIENE IN SCHOOLS 

There are some diseases like typhoid fever, malaria and yel- 
low fever which can be nearly eradicated by sanitation. In- 
fluenza on the other hand is an example of a group of diseases 
for which the greatest hope of control lies in proper personal 
hygiene. During the epidemic of 1918 thousands of people 
died because of the lack of knowledge of the fundamentals 
of home nursing. During this epidemic the visit of the physi- 
cian and nurse was occasional, at best. Many deaths occurred 
because the wife or mother caring for the case did not know 
that the patient with pneumonia must not get up, that he 
needed nourishment regularly even though he did not want 
food and that he must take a reasonable amount of liquids. 
This experience has taught us the need of giving our children 
a better knowledge of hygiene through the school system. 

We have spoken of instruction in mouth hygiene in con- 
nection with the work of the dental hygienist. Other habits 
of hygiene are inculcated by giving the pupil a list of spe- 
cific directions for his daily routine. The following is taken 
from an educational bulletin issued by the Board of Health 
of Bridgeport; 



SCHOOL HYGIENE 295 

MY DAILY KOUTLNE 

1. Have a certain time for rising and keep to it. 

2. Throw bed clothes over foot of bed. 

3. Wash face and hands, neck and ears with hot water and soap. 

Einse off with cold water. 

4. Brush teeth and gums with clear water. 

5. Clean finger nails. 

6. Brush the hair. 

7. Inspect clothes as to cleanliness and see that shoes are brushed. 

8. At breakfast, eat slowly and chew food well. 

9. Visit the toilet, washing afterward. 

10. After breakfast brush the food from the teeth, using tooth powder 

or paste. 

11. Obey rules about entering school; be on time. 

12. Be careful to sit erect and to stand up straight. 

13. Drink water at recess. 

14. Return home to lunch or dinner promptly and wash hands before 

eating and brush hair. 

15. After lunch or dinner brush the food from the teeth, using a 

tooth powder or paste. 

16. Play in the fresh air after school. 

17. Before eating supper, wash the hands and face and brush the hair. 

18. Before taking off the shoes to go to bed, brush the food from 

supper off from the teeth with a tooth poAvder or paste. Pass 
a silk floss or thread between the teeth to remove the food there 
and rinse the mouth with lime water, then rinse with clear warm 
water. This is the most important time to thoroughly clean the 
teeth. 

19. See that clothes are neatly placed in a chair after undressing. 

20. Visit the toilet, washing afterward. 

21. Open bedroom window not less than six inches from top and bottom 

for fresh air. If weather is not too cold, open wider. 

22. Be sure to bathe the body not less than twice a week. 

Such work succeeds best if the interest of the children is 
stimulated by the organization of some child health society 
which has promotions For progress as the child becomes pro- 
ficient or shows a good record in personal hygiene, advancing 
the boy from a "squire" to a "page" to a "knight" etc., with 
corresponding honors for the girls. Children are interested 
in such an organization when properly administered and they 
acquire a pride in physical fitness which lasts all through life. 



296 HYGIENE: DENTAL AND GENERAL 

The teaching of hygiene as a part of the curriculum in 
nearly all of our cities can be improved by making hygiene 
a personal, interesting and novel subject. Within the last 
few years we have made a distinct gain in securing text- 
books which are both interesting and practical. A new 
organization called the Society for Visual Education and 
having headquarters in Chicago is able to supply motion 
pictures on health subjects specially prepared for school chil- 
dren and of high instruction value. Before leaving the gram- 
mar school the child should be given not only the principles 
of personal hygiene but a knowledge of the principles of in- 
fectious diseases so that he will respect the authority and ac- 
tivity of the Health Department and have faith in their 
findings. 

In the high school personal hygiene should be continued and 
perhaps no greater step in improving the health of the nation 
could be taken than to require of every girl a brief course 
in the fundamentals of home nursing. Our discussion of 
school hygiene has already indicated that the normal schools, 
in completing the training of teachers, could supply them with 
the ability to do much for their pupils if they trained them in 
the principles of schoolroom sanitation, the effects of im- 
proper ventilation, lighting and heating and particularly in 
the facts' regarding infectious diseases and the bodily defects 
of children. 

3. SCHOOL HYGIENE AND SANITATION 

The maintenance of proper school hygiene by securing suit- 
able lighting and ventilation, proper seating and proper 
habits of work and play in themselves do much to educate 
the child in matters of personal hygiene. 

The dentist is not ordinarily concerned or burdened with 
the responsibilities for school sanitation. These responsibil- 
ities fall upon the health and school departments. We are 
discussing elsewhere some of the principles of water supply, 
waste disposal, ventilation, heating, and lighting so that it 



SCHOOL HYGIENE 297 

is not advisable to go into detail on this subject, for in any 
case, the public health experts should be consulted and should 
the dentist find himself responsible for regulating these fac- 
tors of school hygiene a more extensive work should be sought. 

There are innumerable details. Safe water must be pro- 
vided and distributed through individual cups or by drinking 
fountains which are so guarded that they cannot be mouthed 
by the children when they drink. Enough light must be sup- 
plied from the pupil 's left or from very high at the right and 
never from the front or rear. The blackboard must receive 
sufficient light and present a dull surface. No seats should 
be so far from the light as to make it difficult for the pupil 
to read. The entrance and cloak room should be sufficiently 
large and properly ventilated with space for hanging clothes 
and a place for wiping the feet. The entrance should not be 
directly on the street and there should be one entrance for 
300 pupils. Windows should be regular with small spaces be- 
tween them and should have small white frames which open 
easily at the top. Dust should be avoided, in so far as pos- 
sible, by wiping boards with a damp cloth and by preventing 
the stirring up of the dust immediately before school or at 
recess since it takes from fifteen minutes to one hour for dust 
to settle. The ventilation system should supply a constant 
change of air at the proper temperature. 

The length and width of schoolrooms should be in the ap- 
proximate ratio of 3 to 2. In room construction, corners 
should be avoided for ease in cleaning. The walls should be 
a light green with the upper three feet whitened and the lower 
five feet may well be of tiling or some such durable material. 
Ceilings should be kept white and the floor of hard wood kept 
smooth. Holes in the floor may be filled with a mixture of 
curd and slaked lime in proportion of five to one. This pro- 
duces a hard waterproof cement. 

The pupil's desk should be selected with care. It should 
not have sharp corners, it should be easy to clean, it should 
not interfere with the teacher's view of the pupil, it should be 



298 HYGIENE: DENTAL AND GENERAL 

noiseless and so shaped that the sitting posture is not likely to 
harm the spine, thorax or the eye. There should be measur- 
ing and reseating of pupils in seats of proper size at least 
two times a year. This is easier if one third of the seats in 
the room are adjustable since classes vary in the size of pupils. 
The top of the desk should be on a plane with the elbow. 
If it is lower than this the spine is injured. The back rest 
should at least support the lower third of the spine. Spit 
cups or cuspidors should be provided if necessary. 

The toilets should be in a convenient place so that retention 
which may lead to maiming or weakening the bladder or pro- 
ducing sex irregularities may be avoided. The toilet should 
be well ventilated and the seat should be sufficiently low and 
U-shaped. Epidemic vulvovaginitis has been reported in 
schools as having spread from toilet seats so high that it was 
necessary for small girls to drag themselves over the front. 

Age and Sex Differences. — There are many other facts 
which must be kept in mind in school administration. The 
brain of the child grows rapidly until the age of seven. The 
school life should not be begun before six and then the change 
should not be abrupt. European examinations (Monnard, at 
Halle, Germany) show that there is less increase in the height 
and weight of the child during the first year of school life 
than in any period up to 14 years of age. This decrease in 
the rate of growth was not noticeable, however, in children 
who did not enter school until the seventh year. Hertel, of 
Copenhagen, found on examination of thousands of chil- 
dren an increase in the amount of illness on school entrance. 

Girls from the age of ten to fourteen years are not as strong 
physically as boys. The Danish Commission examined 16,000 
boys and 11,000 girls and found 29% boys and 41% girls, 
respectively, with sick records. In examining 300 children 
with spinal curvature in Berlin, Eulenberg found that 13% 
were boys and 87% were girls. Books should be carried with 
a shoulder strap like a knapsack and not in one arm, They 



SCHOOL HYGIENE 299 

should not exceed a fifth of the weight of the body. Studies 
have shown more illness in schools of two sessions than in 
schools of one session. 

Standards. — The following* set of Standard Requirements 
for School" Children issued by the U. S. Department of Labor, 
Children's Bureau was prepared by a committee of public 
health experts and adopted at the Children's Bureau Confer- 
ence in Boston in ;May and June, 1919 : 

1. Proper location, construction, hygiene and sanitation of school- 
houses; adequate room space — no overcrowding. 

2. Adequate playground and recreational facilities; physical training, 
and supervised recreation. 

3. Open-air classes and rest periods for pretubercular and certain 
tuberculous children needing some form of special' instruction due to 
physical or mental defect. 

4. Full-time school nurse for not more than 1,000 children to give in- 
struction in personal hygiene and diet, to make home visits to advise and 
instruct mothers in principles of hygiene, nutrition, and selection of 
family diet, and to take children to clinics with permission of parents. 

5. Adequate space and equipment for school medical work and avail- 
able laboratory service. 

6. Part-time physician with one full-time nurse for not more than 2,000 
children, or full-time physician with two full-time nurses for 4,000 chil- 
dren for: 

(a) Complete standardized basic physical examinations once a year, 

with determination of weight and height at beginning and end 
of each school year; monthly weighing wherever possible. 

(b) Continuous health record for each child to be kept on file with 

other records of the pupil. This should be a continuation of 
the preschool health record which should accompany the child 
to school. 

(c) Special examinations to be made of children referred by 

teacher or nurse. 

(d) Supervision to control communicable disease. 

(e) Becommendation of treatment for all remediable defects, dis- 

eases, deformities, and cases of malnutrition. 

(f) Follow-up work by nurse to see that physician's recommenda- 

tions are carried out. 



300 HYGIENE: DENTAL AND GENERAL 

7. Available clinics for dentistry, nose, throat, eye, ear, skin, and 
orthopedic work; and for free vaccination for smallpox and typhoid. 

8. Nutrition classes for physically subnormal children, and the main- 
tenance of midmorning lunch or hot noonday meal when necessary. 

9. Examination by psychiatrist of all atypical or retarded children. 

10. Education of school child in health essentials. 

11. General educational work in health and hygiene, including edu- 
cation of parent and. teacher, to secure full cooperation in health program. 



CHAPTER XV 

INDUSTRIAL HYGIENE 

Dental and Medical service is rapidly increasing in indus- 
try. Already more than 100 firms in the United States have 
fairly complete departments of industrial hygiene which in- 
clude dental clinics. Dental practise in an industry, there- 
fore, is a field which more dentists are sure to enter. For 
those men the subject of industral hygiene holds special in- 
terest. But for the dentist who is sure to continue in private 
practice industrial hygiene has an appeal from two points of 
view. In the first place, he is interested in knowing those 
industrial poisons which have mouth lesions which he should 
recognize in the conduct of his professional activities, and in 
the second place he is interested in knowing what proportions 
industrial hygiene is likely to assume in the near future and 
the attitude of society, the employers and the employees 
toward this subject. A discussion of the subject from this 
point of view naturally falls under three heads: (1) the im- 
portance and social aspects of the problem; (2) the health 
organization of industry; and (3) the industrial diseases to 
be seen in dental practice. 

GENERAL ASPECTS OF INDUSTRIAL HYGIENE 

The health of the worker is a fundamental national problem. 
The great majority of our vast population belong to the group 
of workers, and the social and economic aspects of the ques- 
tion are interrelated with health conditions. Upon the con- 
tentedncss of the industrial classes and upon their physical 
well being rests the stability of our social system. The crafts- 
man of the Middle Ages with an interest in the technique of 
liis work amounting to the professional pride of any genora- 

301 



302 HYGIENE: DENTAL AND GENERAL 

tion, no longer exists. The skill of the hand has been sup- 
planted by the precision of the machine. This change is 
fundamental, for the laborer no longer secures much. of his 
enjoyment of life from his work but endeavors rather to earn 
enough to be able to purchase his amusement out of working 
hours. This important and unfortunate change has deprived 
the worker, in most cases, of a pride in his occupation and 
centered his mind so completely upon the financial return that 
he is not as interested as he should be in the conditions under 
which he works. To be sure labor of late has, in many cases, 
demanded better working conditions; but more instances can 
be found where laborers used unhygienic conditions as a basis 
of the demand for more wages and not as a basis for demand- 
ing better health conditions. 

In the Middle Ages the craftsman had joy and pride in his 
work akin to that of the surgeon or the dentist who is con- 
tinually improving his skill and technique. The old Guilds 
maintained a form of accident and sickness insurance; they 
appointed inspectors to see that the work was properly done 
and honest labor was their watchword. The craftsman knew 
the entire process of making the article on which he was work- 
ing and he knew that his return would be proportional to his 
endeavor. The broad interests and the social organization of 
the Trade Guilds reached a height to which the existing labor 
unions have not attained. 

We are probably moving toward a condition of cooperation 
in industry, but under present conditions it is most difficult 
to give the workman the old time interest in what he is doing. 
He knows only a bit of the process of manufacture, the indus- 
try is so large that he is widely removed from the man at its 
head; there is in many cases worse than a lack of sympathy 
between employer and employee, and the high labor turnover 
testifies to the lack of interest of the workman in his partic- 
ular factory. The return of the worker 's interest in his work 
and in the conditions of labor would greatly aid the prog- 



INDUSTRIAL HYGIENE 303 

ress of the health movement. But the latter movement need 
not be delayed for the former, for its solution will help to solve 
the economic problem. 

This unfortunate industrial condition of class selfishness in 
which labor and capital with mutual dislike and distrust both 
profiteer to such an extent that unskilled or semi-skilled labor 
receives more money than the average man in the professions, 
while capital merely adds the cost of increased wages to the 
sales prices and thereby increases both the value of its prop- 
erty and the rate of its return, is unfortunate from the eco- 
nomic point of view. But industrial distrust in place of in- 
dustrial cooperation is even more objectionable from the view- 
point of health. 

It has recently happened, for example, that the labor unions 
of a great industry objected to the continuation of physical 
examinations. The reasons given were that physical examina- 
tions give an industry the opportunity to spread propaganda 
favorable to capital among its workers ; that there is an oppor- 
tunity for the industry to discharge "labor" men by declar- 
ing them physically unfit ; that the bodies of the men are their 
own and that capital has no right to have an inspection ; that 
the physician who is examining the men will testify against 
them in court if they have a case against the company for in- 
dustrial accident; that industries try to secure the goodwill 
of the general public by expanding the health work for em- 
ployees. 

Physical examination of workers as carried on by most 
industries, coupled with the attempt to relieve those body de- 
fects which are found, is not a selfish move on the part of the 
industry and such objections as are raised above — and which 
do not need an answer in a discussion for professional men — 
would almost make it appear that the desire to broaden the 
gulf between labor and capital is dominant in the mind of 
the labor leader who makes these objections. His interest in 
the welfare of the worker and willingness .to improve indus- 
trial relations does not appear. It does happen that a healthy 



304 HYGIENE: DENTAL AND GENERAL 

worker, free from bodily defects and therefore more efficient 
and contented, is more profitable to the industry than the 
same man encumbered by the body defects with which he fre- 
quently seeks employment, but the workman who objects to 
being made well and happy through the efforts of his own 
doctor or those of the industrial physician, surgeon or den- 
tist, following the examination which has revealed these de- 
fects, comes pretty near cutting off his nose to spite his face. 

General Problems . — There are many considerations in the 
regulation of industry . which apply to industries generally 
and which are regulated both from without by the state and 
from within by the industrial management and the demands 
of organized labor. I refer to such problems as the hours of 
work, fatigue, child labor and women in industry. These ques- 
tions with their interrelationships have such a universal ap- 
plication that it is the duty of the state, first, to study b3^ 
observation and research the conditions of employment; 
second, by careful legislation to regulate conditions in a sane 
and practical manner and, third, to enforce the law by an 
efficient organization for factory inspection, 

Hours of Work. — The number of hours which an individual 
may work depends largely upon the nature of this work. If 
labor were paid on the basis of production and interested in 
maximum production, it would be possible to arrange for each 
occupation the hours of labor in accordance with greatest 
efficiency without injuring the health of the worker. So far 
as the state is concerned, however, it must deal with industries 
in large groups and set standards of labor in terms of hours 
per week beyond which either health or production or both 
are likely to suffer. 

The experiences of the great allied countries during the war 
have taught us much in this regard and the investigations be- 
gun under war conditions are likely to be continued, greatly 
to the profit of industry. These reports* show a reduction in 

*Report of the ileatth of Munition Workers, Committee of the Ministry of 
Munitions, published by His Majesty's, Stationery Office, London, 1918. 



INDUSTRIAL HYGIENE 305 

hourly output during the later hours of the 8, 10, and 12 hour 
working day, the reduction being greatest in the last instance. 
The relative benefits of a ten minute rest period in the eight 
or ten hour day and the great advantages of Sunday rest are 
described. Perhaps no more striking fact was brought out 
than the discovery that the weekly production on the six day 
basis was equal to or greater than the weekly production on a 
seven day basis. 

Fatigue. — Actual and careful studies within industries 
made by expert physiologists are rapidly producing a new sci- 
ence of industrial hygiene and physiology. The U. S. Public 
Health Service is making important investigations from which 
we may hope to learn much concerning the effect of fatigue 
in increasing the number of accidents, in decreasing produc- 
tion, and in injuring health. The great need in this field at 
present is further scientific investigation of fatigue in the 
various kinds and conditions of labor. These studies will 
show us how fatigue may be reduced by modifying processes, 
and by selecting the right type of man for each type of work. 
They will point out the unnecessary causes of fatigue and 
show what innovations may be made to avoid them. 

Child Labor. — Many states already have good laws prohibit- 
ing the employment of child labor, but even the best of these 
states have inadequate machinery for inspection and enforce- 
ment. It is to be hoped that the new and second national 
child labor law may be found to be constitutional and go far 
toward remedying these conditions. The unrestricted em- 
ployment of children in industry interferes with their physical 
•<\)\([ mental development, and moreover, children have been 
found to be subject to industrial accident and industrial dis- 
eases to a greater degree than adults. 

Women in Industry. — Special legislation is frequently nec- 
essary to safeguard the health of women because they lack 
strength for undertaking many occupations, and in addition 
there is a period each month during menstruation and a longer 



306 HYGIENE: DENTAL AND GENERAL 

period at the termination of labor when heavy employment 
should not be allowed. Most states require that a woman 
shall cease work from two to four weeks before labor and that 
she shall not recommence work until four weeks after the 
birth of the child. Although infant mortality increases di- 
rectly with the proportion of women working outside the home, 
it is perhaps unfortunate that states cannot legislate regard- 
ing woman 's work in the home which, in many cases, is heavy, 
prolonged, worrisome, and fatiguing beyond that of factory 
employment but which receives very little consideration and 
is difficult to remedy. 

Factory Inspection. — Factory inspection involves the en- 
forcement of laws regulating ventilation, dusts, gases, odors, 
temperature, moisture, light, cleanliness, overcrowding, water 
supply, washing facilities, water closets, lockers, fire preven- 
tion, the safeguarding of machinery, first aid facilities, hours 
of labor, employment of women and children, ages of employ- 
ment, etc. In many states the enforcement of these laws 
is under the State Department of Health and enforcement is 
a reasonable duty of the Division of Industrial Hygiene. In 
other states, however, it is under a separate Department of 
Labor, and Industries but when so located it demands much 
attention from the medical viewpoint, especially in these times 
when so much is being learned regarding poisons and other 
industrial hazards. No state can be excused for not investi- 
gating and trying to lessen the health and accident hazards 
of the industries within its borders. 

Industrial Accident Insurance. — The history of Employers' 
Liability Acts which originated in Europe and which were 
later supplanted both in Europe and America by industrial 
insurance describes a step forward in industrial relations. 
Under Employers' Liability the workman recovered damages 
for injury by accident by bringing suit against the employer 
and it was necessary for him to prove that the accident was 
due to the fault or negligence of the employer rather than to 
his own fault or that of a fellow worker. Naturally ill will 



INDUSTRIAL HYGIENE 307 

arose between the contending parties ; the amount of damages 
granted often depended upon the case and the court rather 
than upon the extent of the injury; and there was usually 
a long delay before the stricken family of the injured worker 
received any benefit. 

Society has gradually come to assume that the industry is 
responsible for all accidents occurring in its processes and that 
the workman should be paid promptly and in proportion to 
the injury or incapacitation incurred in the execution of his 
duties as an employee. Accordingly most of our states have 
now enacted industrial insurance acts under which the em- 
ployer insures his liability with the state or with an independ- 
ent insurance company. Under such a law the employee re- 
ceives benefits from any accident incurred in the industry and 
from diseases contracted because of occupation. It is not nec- 
essary for the workman to prove that the accident was the 
fault of the employer since no difference is made between 
payment in such accidents and in those due to the fault of the 
worker, unless malicious or intentional. Under this system 
the workman receives compensation after a waiting period of 
about ten days; there is no delay or expenditure for court 
procedure, and the friction between employer and workman 
is banished. 

HEALTH ADMINISTRATION IN INDUSTRY 

Health activities in industry are usually carried on under 
a service department and under the administration of a Serv- 
ice Manager who reports directly to the General Manager. 
The chart on pp. 308 and 309 used with permission of the 
Hood Rubber Company gives the organization and activities 
of one of the most complete and successful service depart- 
ments in the country. 

In industries where the service department has been given a 
fair trial under tactful and efficient leadership, it has clearly 
demonstrated its usefulness and both employers and em- 




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310 HYGIENE: DENTAL AND GENERAL 

ployees have come to regard it as a normal and natural serv- 
ice which the manufacturer should render to the workman 
under the conditions of his employment. More than that it 
gives opportunity for the employee to better his own con- 
ditions and those of his fellow workers, thus making a job into 
a career and a mechanical operation into a human relation- 
ship. It is a new and proper service from the manufacturer 
which is bound to develop as has accident insurance and which 
will soon cease to be resented as "charity" by the workman, 
provided of course that it is properly administered. 

The activities of the service department are seen to be 
numerous and varied. The service manager must first of all 
be a good administrator ; he must know the industry ; he must 
understand men and he should be familiar with the facts con- 
cerning health and sanitation and the principles of health' 
administration. He may be a sanitarian or a physician by 
training but in any case he is, in a large organization, an 
administrator and can secure expert services and delegate 
either the medical or engineering responsibility. 

It does not lie within the scope of this volume to describe 
the multiple activities of a service department. The number 
undertaken and the details of administration vary widely. 
The reader is most interested in the strictly medical and 
dental phases and the discussion will be limited accordingly, 
allowing only for such comment upon accident prevention and 
sanitation as will show the close relationships which they bear 
to health improvement. 

Accident Prevention. — Scientific accident prevention has 
been adopted by nearly all of the great industries where 
hazards are numerous and it has succeeded because it is prac- 
tical. It has been demonstrated that by properly safeguard- 
ing machinery and dangerous processes and by organizing the 
men for safety, the number of accidents can be markedly re- 
duced. Accident rates have been reduced 80 per cent in 
some industries and it is estimated that 25 per cent of this 
reduction was due to mechanical safeguards and 75 per cent 



INDUSTRIAL HYGIENE 311 

to thoughtful precautions taken by the men themselves as a 
result of "Safety First" teachings. This reduces the suffer- 
ing of the men, makes the work more desirable and it reduces 
the expenses of insurance and medical attendance. 

Safety engineers have often been men without an engineer- 
ing training but men of good mixing ability who understood 
the industry and who were able to organize the men into 
safety committees and follow up accidents to see that the 
proper remedies were applied for dangerous conditions. It 
has happened frequently that safety engineers have also been 
interested in the sanitation of the plant and sometimes to an 
even broader extent in the health of the men. It is often 
desirable that a man should be secured for this work whose 
training enables him to combine sanitation and safety. 
Trained men will soon be demanded for both lines of work. 

Industrial Sanitation. — The duties of the sanitary en- 
gineer in the industry are, as in general practise, the pro- 
vision of water supply and waste disposal to which are likely 
to be added problems of lighting, heating, and ventilation. 
Principles involved in these activities are discussed elsewhere 
and the particular problems of industrial sanitation are not 
of interest to the dental practitioner. The supervision of eat- 
ing facilities at the factory will serve as an illustration of the 
direct relationship between sanitation, other health activities, 
and the health and efficiency of the employee. 

Food. — The supervision of such restaurants as may be main- 
tained in or near industries may logically be mentioned as a 
part of the sanitation of the industry but the food problem 
is more than this. Of course the sanitation of the restaurant, 
the physical examination of food handlers, clean, pasteurized 
milk, adequate dish washing facilities for complete steriliza- 
tion and sanitary wash rooms and toilets for food handlers 
must be provided. But the food problem does not end here. 

In the steel-ship industry the author found that among 
60,000 men in about 40 shipyards from 66 per cent to 90 per 
cent brought their lunches. These lunches were eaten cold 



312 HYGIENE: DENTAL AND GENERAL 

and in most cases were not balanced from the dietetic stand- 
point. Moreover many men who bought lunches at the cafe- 
terias paid fifty cents for their lunch, selecting nothing but 
desserts and many of these were of the pie crust and whip 
cream variety with relatively little nourishment. In this in- 
dustry it was possible to secure improvements by placing cus- 
tards, bread puddings, blanc mange, and other nourishing 
foods on the list of desserts and by placing booths at various 
points about the shipyard from which hot coffee and hot stew 
were served in sanitary individual containers to supplement 
the cold lunches brought from home. 

By enlisting the help of the community health organizations 
in the food program, it was possible to secure practical demon- 
strations of how to prepare suitable lunches with a saving in 
expense, and further suggestions were supplied through 
columns of the monthly paper issued by the industry. The 
results of the campaign were most gratifying and the incident 
illustrates how sanitary and medical supervision, health edu- 
cation and the cooperation of the shop committees, the man- 
agement and the health interests of the community must often 
combine for a health improvement. 

Medical Activities. — The medical organization of an indus- 
try is to maintain the health of the working force and its ob- 
ject is threefold; first, to care for the man who becomes sick 
or injured while at work; second, to detect and correct defects 
which are remedial; and third, to detect diseased conditions 
in new employees which would endanger their own lives or 
those of their fellow workmen thus making it possible to tem- 
porarily exclude or restrict the employment of this type of 
worker. This very important function is mentioned last be- 
cause many medical departments exist where there is not as 
yet either a physical examination upon employment or a 
periodical examination of the workers. The United States, 
our greatest employer, has recently examined what was at the 
time its most important group of workers (soldiers and sail- 
ors) and has attempted to remedy some of the physical de- 



INDUSTRIAL HYGIENE 313 

fects found. These men were picked from the age groups 
in which they are supposedly most vigorous and even then 
from one third to one half of them were unfit for full military 
service. The following are the physical defects found : 

TABLE SHOWING CAUSES FOE DBA FT REJECTION 

PER CENT 

CAUSES ALL 

REJECTIONS 

Total rejections, for all causes 100.00 



Alcohol and drugs 43 

Eones and joints 12.35 

Development defects (height, weight, chest measurements, muscles) 8.37 

Digestive system 53 

Ears 4.38 

Eves 10.65 

Flatfoot (pathological) 3.87 

Genitourinary (venereal) 1.33 

Genitourinary (non-venereal) 1.35 

Heart and blcod vessels 13.07 

Hernia 6.04 

Mental deficiency 5.24 

Nervous and mental disorders 5-07 

Respiratory tuberculosis) 8.67 

Respiratory (nontubereulosis) 1-67 

Skin 2.68 

Teeth 3 - 16 

Thyroid 1J6 

Tuberculosis (of parts other than respiratory) 88 

All otli< r defects 3 - 06 

Cause not given 5.44 

The industry is in much the same position as the govern- 
ment. It not only owes to the individual compensation for 
accident or illness acquired as a result of his occupation, but 
it also owes to the individual a knowledge of his physical con- 
dition, and the applicant should be so placed in the industry 
as not to aggravate his physical condition. It owes to the 
workers already in the planl protection against the entrance 
of infectious disease. 



314 hygiene: dental and general 

A great service can be rendered in improving the health of 
the industrial class by offering free medical examination. The 
workman is warned of a defect while it is still remediable and 
the yonng man is impressed with the importance of health 
when he looks forward to a physical examination as part of 
the process of "getting a job!" It may seem to the private 
practitioner of medicine and dentistry that the individual 
should merely be apprised of his physical condition and that 
he should seek medical treatment outside the industry. This, 
of course, is what happens in a great number of cases. The 
worker always possesses the right to choose his physician and 
mode of treatment and frequently prefers to go to his family 
physician or dentist. On the other hand, however, there is 
no reason why the industry should not, if it chooses, offer to 
the workman medical and dental care free or at slight cost. 
The industry can frequently afford to do so as there is less 
lost time for the industry and for the employee when treat- 
ment is given at the factory. 

The employee is insured against industrial accidents and 
industrial diseases and there is no obligation upon the indus- 
try or the insuring company to treat anything more than acci- 
dent cases. Even where there is not a well organized service 
department, however, it is usually the policy to treat em- 
ployees for minor ills such as headache, toothache, stomach 
cramps and the like, for which it is known they would not be 
likely to consult a physician. 

An example of the value of a medical department may be 
seen in the experience of an industrial establishment (Modern 
Hospital, July, 1919) which offered optional physical exami- 
nations under the supervision of the Life Extension Institute 
beginning in May, 1915. Seventy per cent of the workers were 
examined and examinations were repeated in the three suc- 
ceeding years. Later it was made compulsory for new employ- 
ees. Out of 599 examined, only 5 were found to be normal; 
594 required advice regarding their living habits or physical 
condition; 377 were directed to a physician, and of these 317 



INDUSTRIAL HYGIENE 315 

were not aware of any impairment whatsoever. The em- 
ployees who, by later investigations, were found to be carry- 
ing out instructions numbered 361 ; those carrying them out 
partially, 66 ; those making plans to do so, 12 ; those who had 
done nothing, 160. Hence 439 of the employees have, or will 
have been benefited. Poor eye-sight, teeth, heart disease, and 
incipient tuberculosis are particularly mentioned. 

If the industrial physician or dentist is efficient and under- 
stands his position and the relationships of his department to 
the workmen in the plant, the medical department is an aid 
to the industry in many ways. The industrial dentist and 
physician may be nearly or completely engrossed in admin- 
istering professional services which only slightly differ from 
those of private practise, although there are certain indus- 
trial diseases with which both must be familiar. However, 
to be successful each must carry, in addition to his professional 
knowledge, the ability to command the friendship and respect 
of the men who come to him for treatment and to impress 
upon his patients the value and propriety of the sort of work 
he is doing. The dentist must not allow the false idea to exist 
that the dental clinic is a "patronizing" activity. It is a 
function of the industry to which the workman is entitled and 
it can only be successful by an appreciation of its usefulness 
and by the cooperation of the workmen in the factory. The 
policy of the hospital and clinic must be clearly established 
and thoroughly understood by the medical and dental person- 
nel and by the management, and this policy must be strictly 
adhered to. The same dignity should be maintained as in 
private practise and under no conditions should the clinic be- 
come a place for loitering or for unreasonably frequent visits 
by employees. 

Industrial Dentistry. — It is not difficult to prove the need 
of dental care for the industrial worker. In examining large 
groups of industrial workers, it has been found that 90 per 
cent or more of such people have dental defects. Thousands 
of men were excluded from general military service because 



316 HYGIENE: DENTAL AND GENERAL 

of dental defects, and it is no wonder that now — when an in- 
creasing number of bodily defects are found to be due pri- 
marily or in part to local infections about the teeth — the im- 
portance of expert dental services begins to receive general 
recognition. 

The dental clinics which have been established in various 
industries are not uniform in their methods of administration. 
The dentist may be full time or part time. Some industrial 
clinics give only an examination and the dental work is done 
by an outside dentist. Some give examinations and clean the 
teeth and some not only give examinations but the additional 
services of cleaning, filling, extraction, bridge, crown and plate 
work. Some even go so far as to give free dental services to 
the children of employees. In other industries dental work 
is not free but at the employee's expense although it may be 
done in the company's time. In still other industries where 
physical examinations are given by physicians, an arrange- 
ment is made with an outside dentist or dispensary to do the 
dental work for the industry at a reduced cost. 

The description of the dental clinic at the home office of the 
Metropolitan Life Insurance Company as described by Dr. 
Lee K. Frankel, is very interesting and instructive. (Taken 
from "Industrial Medicine and Surgery" by Harry E. 
Mock.) 

The clinic was opened July 1, 1915. The equipment was the best ob- 
tainable. It included: 

Four S. S. White-Evans-Forsythe Dental Units, which consist of 
chair, bracket, engine, cuspidor, and compressed air attachment. 

Four S. S. White Lyons operating stools. 

Four electric spray heaters. 

One Bitter Columbia dental chair. 

One Bitter dental engine. 

One electro-dental switchboard. 

One Waugh radiographic machine and lead screen. 

Two sterilizing outfits. 

Four small cabinets. 

One large dental cabinet. 

One metal and glass linen cabinet. 

Complete set of instruments, towels, bibs, etc. 



INDUSTRIAL HYGIENE 317 

It was planned that the work should be limited to a careful exami- 
nation and cleansing of the employees' teeth each six months. The re- 
sults of the examination are charted and copies of the charts are given 
to the employees, indicating what subsequent treatment will be necessary 
by their own dentists. 

A follow-up system was inaugurated to ascertain whether the neces- 
sary attention is given. Xo attempt was made to require or compel 
employees to come to the clinic. From time to time addresses Avere de- 
livered by the dentists in charge to the employees, indicating the value 
of proper care of the teeth. 

There are approximately 5,000 employees in the company's service 
at the home office; 2870 treatments were given to 2707 patients in the 
first six months, July 1, 1915 to December 20, 1915. In the second six 
months 3383 treatments were given to 2843 patients. In the first six 
months the average time required for examination and cleansing was 
approximately sixty-six minutes. With the experience gained by the 
dentists in charge, this was reduced so that in the second six months the 
average time was forty-nine minutes. The average time required is con- 
stantly decreasing. Viewed month by month this is shown very clearly. 
In January 1916, the average time was sixty-three minutes, in February 
fifty-four minutes, in March fifty-three minutes, in April forty-eight min- 
utes, in May forty-seven minutes, and in June thirty-five minutes. 

The clinic is in charge of Dr. Thaddeus P. Hyatt, who has under him 
four assistants and a radiographer. Seven women are employed in the 
dental clinic as assistants to the dentists, as telephone operators, in the 
sterilizing room, etc. All the dentists are full-time employees with the 
exception of Dr. Hyatt. The service given to the employees is free and 
on the company's time. 

I am giving you, herewith, the statistics for the second six months, 
namely; Jan. 1, 1916 to June 30, 1916, as these are probably more in- 
dicative than would be those in the first six months of the service. In 
this time prophylactic treatment was given to 2315 patients and emer- 
geney care to 528 additional patients, making a total of 2843 patients 
cared for in the period. The average time for emergency cases twenty- 
one and one-half minutes. Under this term is included: treatment for 
abscesSj pyorrhea, exposed pulp, gingivitis, pulpitis, pericementitis, in- 
fected tooth socket, toothache, and extractions and consultations. 

The cost of the entire service was $7,229, or an average of $3.00 per 
hour, and an average per patient of $2.33. Subdividing the prophylactic 
work from the emergency work, the cost per patient for the former was 
$2.46 and for the emergency work the cost per patient was $1.06. As- 
suming that employees accept service of this kind each six months, the 



318 HYGIENE: DENTAL AND GENERAL 

cost per treatment per patient per annum would, of course, be double 
the figure given per employee treated. 

The results even this far obtained are of considerable interest: of the 
clerks who appeared in the first six months, 1636 who showed cavities on 
the first examination reappeared during the second six months. These 
clerks on the original examination had 7,753 cavities or an average of 
4.6 cavities per person. During the interval between the first and second 
examination 916 clerks (56 per cent) out of the 1637 who had cavities 
had 2936 fillings made, or an average of 3.2 fillings per clerk. 

There are other evidences of improvement although they are not of 
such importance. At the time of the first examination 3.9 per cent of 
the clerks did not use a toothbrush. At the second examination it was 
found that this had been reduced to 2.9 per cent. At the time of the 
first examination 32.9 per cent of the clerks did not show clean mouths. 
At the second examination only 22.5 per cent showed such condition. 

The dentist must realize keenly any special dangers to the 
teeth which may be inherent in the various processes of the 
industry, and it is his duty by both prophylaxis and education 
to safeguard the worker's health in this respect. Frequently 
an employee reports to the hospital with what he believes to 
be an industrial disease when in reality he is suffering from 
systemic effects arising from decayed or abscessed teeth which 
may or may not have a relationship to the industrial process 
in which he is engaged. 

Disease Prevention and Health Education. — Every member 
of the medical department should appreciate the value and 
saving of disease prevention. And this activity must have 
the hearty support of the men in the industry if it is to be 
successful. Just as 75 per cent of accident prevention de- 
pends upon the Safety Organization of the workers, so health 
is acquired, maintained or lost by the individual. Health is 
like salvation; no one can secure yours for you. Health 
education in industry should not be built from the top down 
but from the bottom up. The general manager cannot limit 
preventable disease but the willing cooperation of the workers 
can do it. The health expert in industry who can interest 
and organize the men and women of the factory for health 
betterment both in the shop and in the community will ac- 



INDUSTRIAL HYGIENE 319 

complish more than a reduction in the morbidity rate. For 
after all life is not a matter of the pay envelope and the 
more men and women of the industrial class are interested in 
the conditions of the home, the conditions of labor, the 
health and welfare of their families and their fellow men, the 
more efficient will be our industries, the more stable our popu- 
lation, and the more intelligent our government. 

INDUSTRIAL DISEASES 

The dentist should know the industrial diseases which have 
mouth lesions and the industries in which they occur. In the 
case of those industrial poisons which like acids hasten the 
decay of teeth, it will naturally be the part of a dentist em- 
ployed in an establishment to prevent the injurious effects of 
the harmful substance by keeping a careful and continual 
watch over the dental conditions of the men in that branch of 
the industry and by prophylaxis and instruction to teach 
them to avoid the dangers incident to their work. We shall 
briefly discuss the important industrial diseases which have 
mouth lesions ; but the dentist who is working over people em- 
ployed in trades where any one of the industrial diseases 
exists would want to consult the references and study such 
diseases in much greater detail. 

Lead Poisoning. — Lead is a common cause of serious poison- 
ing. It is not readily eliminated from the body and even 
small amounts which are swallowed or absorbed through the 
respiratory tract or the skin soon accumulate in serious quan- 
tity. One of the early symptoms of lead poisoning which may 
be seen even before serious physical defects are noticed is the 
blue line on the gums. This is usually a double line: a line 
upon the teeth just below the gum which may be removed by 
washing and another line upon the gums themselves and con- 
sisting of lead sulphite which has been thrown down at this 
point. The susceptibility to lead poisoning varies and young 
adults are most susceptible, women being more susceptible 
than men. 



320 HYGIENE : DENTAL AND GENERAL 

Lead is poisonous in almost any form although the soluble 
salts like the carbonates are more dangerous than the in- 
soluble salts like the sulphates. For this reason, lead carbon- 
ate is eliminated from industries wherever possible. The most 
common methods of poisoning by lead are by the inhaling of 
lead dust, or by swallowing lead which is carried to the mouth 
in various ways by the hands. Absorption of the soluble lead 
salts through the skin may take place but this type of poison- 
ing is relatively unimportant. 

Other symptoms of lead poisoning include restriction of 
the secretion of saliva, a sweetish taste in the mouth, weak- 
ness, weak pulse, constipation, high blood pressure and anemia. 
Later developments may include wrist drop and encephalitis, 
which appears as an acute insanity. This poisoning is par- 
ticularly dangerous where women are employed. 

Phosphorus Poisoning. — A serious disease resulting from 
phosphorus poisoning is known as "phoss}^ jaw." There is 
an extremely painful inflammation of the jaw bone in the 
early stages which later becomes chronic and produces a local- 
ized degeneration of the bone. The phosphorus produces 
either a septic gingivitis by inflaming the gums or an active 
inflammation by acting through decayed teeth. In either case 
there is soon pus formation in the swollen gum and the pain- 
ful jaw bone. There are two kinds of phosphorus ; the white 
or yellow which is highly poisonous and the red or amorphous 
which is practically nonpoisonous. 

Phosphorus poisoning was most common in the match in- 
dustry but the modified methods of making matches have for- 
tunately nearly eliminated the disease. In place of the old- 
fashioned phosphorus match we have a match made with the 
nonpoisonous sesqui-sulphid of phosphorus. The "safety 
match" contains potassium chlorate or chromate with other 
oxygenous substances and is scratched on a special surface 
which contains antimony sulphid and red phosphorus. Phos- 
phorus poisoning still occurs where certain special processes 
— like the manufacture of bone black, phosphates or rat pois- 
ons — are carried on. 



INDUSTRIAL HYGIENE 32l 

Mercury Poisoning — The indications of mercurial poison- 
ing are ulcerations of the gums, loosening of the teeth, pain 
and swelling in the salivary glands, headache, anemia, tremor 
of the muscles, depleted breath and dizziness. Frequently the 
molar teeth are lost and the other teeth are black and eroded 
from the acid solution. 

Mercury is absorbed through the respiratory system, the 
skin or the digestive system. Edsall has cited cases in dent- 
ists who had the habit of working their amalgam in the palm 
of the hand and thus absorbed mercury through the skin. 
Poisonings most frequently occur from the amalgam used in 
separating gold and silver ore and from the mercuric nitrates 
used in the fur dressing industry. 

Benzene Compounds. — Among the other substances which 
produce mouth lesions may be included benzene which some- 
times produces a chronic poisoning with pupuric hemorrhage 
of the mucous membranes of the mouth and throat. Aniline 
and nitro-benzene both produce a definite cyanosis of the lips 
and face usually spoken of as the "blues." These and other 
benzene compounds produce serious effects upon the nervous 
system. The poisons do not affect the teeth, but they might 
be detected in the dental practise and referred to a physician. 

Acids. — The metallic acids are used in many industries and 
unless suitable care is taken they produce serious effects by 
dissolving the dentine of the teeth. Hydrochloric, sulphuric 
and hydrofluoric acids are the most common offenders. Pic- 
ric acid in addition to its injurious effects upon the teeth pro- 
duces an inflammation of the mucous membrane of the mouth. 

Protection Against Industrial Poison. — It has been seen 
that some industrial poisons are given a greater opportunity 
to act where defective teeth are present, but in addition to 
putting the teeth in first class condition there are other 
measures of precaution which need to be taken to protect the 
the industrial worker. These include proper instruction con- 
cerning the nature of the industrial hazards, the installation 



322 HYGIENE: DENTAL AND GENERAL 

of suitable ventilation to remove dust and fumes, the instal- 
lation of wet processes for dry and dusty ones where possi- 
ble, the use of proper protective clothing, and the liberal use 
of washing facilities which should be adequate for the working 
force. For a consideration of these matters, the reader must 
consult a more extensive work on the subject of Industrial 
Hygiene. 



CHAPTER XVI 

VENTILATION, HEATING AND LIGHTING 

The ventilation, heating and lighting of a man's place of 
work and his home directly affect his health and the health 
and comfort of his family. The professional man often fails 
to realize that the poor ventilation and lighting of his office 
increases both the discomfort and the irritability of his pa- 
tients or guests. Everyone at some time or other has felt 
the oppressiveness of the air upon entering a poorly ventilated 
room. We are sensitive to certain changes of temperatures 
and barometric conditions. We appreciate the unusual fa- 
tiguing effect of a day 's work in an office when the ventilation 
is poor, and we have high regard for the stimulating effect of 
outdoor life at the seaside or in the moutains during the sum- 
mer. Everybody knows that there is a difference between 
good air and bad, but too few people know in what that dif- 
ference consists and still fewer people have the energy and 
courage to insist upon suitable ventilation in office, home or 
public buildings. 

GOOD AIR DEFINED 

The old idea that the quality of air is determined by its 
chemical characteristics has been found to be wrong. As chil- 
dren most of us were taught that bad air was air poor in 
oxygen and loaded with carbon dioxide. It w T as thought that 
poor air must contain too little oxygen to supply the demands 
of the body, and that carbon dioxide acted as a body poison. 
Recent physiological experiments have shown that, contrary 
to the former belief, it is the physical and not the chemical 
character of the air which determines its quality. A compar- 
ison of the oxygen and carbon dioxide contents of outdoor air, 
exhaled air, and the air of poorly ventilated rooms shows the 
reasonableness of the discovery. 

323 



324 HYGIENE: DENTAL AND GENERAL 

Oxygen and Carbon Dioxide Content of Different Kinds of Air. 

Oxygen Carbon dioxide 

Composition of pure air 21% .04% 

Air in the lungs 16% 5.00% 

The air in the worst ventilated rooms. . .19% .40% 
Composition of air which chemically pro- 
duces physiological injury 14% 3.00% 

It is to be noted that there is a wide difference between 
"close air" and air which produces injury by virtue of its 
chemical composition. Even in the worst ventilated room the 
air is chemically much better than that in the lungs. 

Until very recently little attention was paid to the effect of 
air upon the skin, although now we recognize it as most impor- 
tant. It is hard to believe that the soft free air can make us 
uncomfortable by its contact with a thick tough structure 
like the skin until we realize that our skin not only receives 
the external contact stimuli but also helps to regulate the body 
temperature as it is acted upon by the air from without and 
the nervous system from within. 

It is easy to forget that the skin is a sense organ, for unless 
we are either chilled or perspiring other more important 
thoughts and stimuli crowd these minor sensations into ob- 
.livion. It is like the ticking of a clock to which we have be- 
come accustomed. We work in the room and are not conscious 
that the clock is present and yet if it stops we are immediately 
aware of it. 

The movement of air against the body produces definite 
sensations as it is easy to demonstrate. Step from the breezy 
porch of your summer cottage into a room with the doors 
and windows closed so that there is no movement of the air. 
Sit for a few minutes quietly and then return to the porch 
and see if the breezes do not have a pleasing and stimulating 
effect. The deadening effect inside the room was due to the 
fact that the air immediately about the body, the aerial 
blanket, was not being rapidly changed. There was very 
slight movement of air in the room and the clothes held this 



VENTILATION, HEATING AND LIGHTING 325 

"blanket" closely wrapped around the body. If we go out, 
from a warm room in winter weather we notice a definite and 
marked reaction of the skin. Similar but lesser reactions are 
continually taking place in adjusting the body to the chang- 
ing condition of air and no doubt the body receives an im- 
portant stimulation from this gentle playing upon the nerv- 
ous system by the changing air. 

These considerations are in harmony with the results of ex- 
periments conducted by the New York Ventilating Commis- 
sion and by other investigators. For example, a man is put in 
a closed box where the air is hot and moist. A feeling of dis- 
comfort soon develops which cannot be relieved by feeding the 
man air from the outside by means of a tube passed through 
the wall of the box. The symptoms of discomfort are relieved 
by turning on an electric fan inside the box, even when the 
subject breathes the air from within which has been vitiated 
by continuous breathing. On the other hand, a man sitting 
outside the box in air of proper temperature and humidity 
is not injuriously affected by breathing through a tube which 
supplies him with air from within even though it is vitiated, 
hot and moist. The effect is on the skin not on the lungs. 

Experiments have failed to demonstrate the presence of any 
injurious organic substance or "crowd poison" in breathed 
air although it has been found that disagreeable odors pro- 
duce a depressing effect upon the appetite. 

We deduct from the foregoing statement that the most 
important problem in ventilation is a suitable change of the 
aerial blanket, and that moving air of the proper tempera- 
ture and humidity, the wearing of clothes which allow rea- 
sonable ventilation to the skin, and the use of water and air 
baths to keep the skin clean, are the primary considerations. 
The important considerations in air supply are a comfortable 
temperature and a suitable humidity. It is indeed foolish 
for fresh air cranks to advise poor people to suffer with the 
cold because they "need to have the windows open to secure 
fresh air," 



326 HYGIENE: DENTAL AND GENERAL 

Temperature. — If we examine the effect of different tem- 
peratures upon the body, we find that if the temperature is 
between 80° and 100° F. the body adjusts its heat-regulating 
mechanism so that it just keeps pace with the loss of heat 
from the body by the evaporation of perspiration and by heat 
transfer, (i. e., radiation and conduction). The optimum tem- 
perature is 68° F. Slight variations from this temperature 
will not quickly call the heat-regulating mechanism into op- 
eration so that discomfort may be felt between 60° and 75° 
because it is neither so warm as to start active perspiration 
nor so cold as to require active movement. If the temperature 
is below 65° and above 40° such a chilliness is felt that if 
the person is free to do so he will move about and thereby 
increase the body temperature by greater oxidation. It has 
been suggested that the feeling of discomfort arises from the 
difficulty which the heat-regulating mechanism is experienc- 
ing. 

Moisture. — What effect does the varying moisture content 
of the air have upon the body? We know that water is a 
good conductor of heat and therefore if the air is moist and 
cold it will seem very chilly because . the heat is conducted 
away from the body rapidly, even though the skin has re- 
acted to the low temperature and reduced the evaporation 
of moisture. On the other hand, if the day is very hot and 
the air is moist the evaporation of perspiration will be less 
rapid because the air is already loaded with moisture. This 
prevents the body from cooling itself by the process of evap- 
oration. It thus appears that a moist air seems colder at 35° 
and warmer at 95° than dry air at the same temperatures. 
In either case an increase in the movement of the air would 
make it seem colder or cooler because moving air continually 
changes the aerial blanket and increases heat transfer and 
evaporation. 

Odors. — We have said that disagreeable odors are injurious 
to health in having a definite effect upon the appetite. They 



VENTILATION, HEATING AND LIGHTING 



327 



probably also irritate or depress the nervous system. To be 
sure the olfactory nerve soon becomes tired and insensible to 
a given odor but the depressing effect no doubt continues. 

The nose can always detect a new odor or a different odor 
and for this reason the odor of the air is a good index of its 
freshness or staleness when one first enters the room. Odors 
arise from foul breath, an unclean mouth, decayed teeth, ca- 
tarrh, the sudoriferous glands from the feet and axillae, and 
from the decomposition of organic matter on the skin and 
clothes. Moisture is always necessary for the detection of 
odors and they therefore become more objectionable as the 




Fig. 49. — Wet and dry bulb thermometer for wall attachment. (Courtesy of the 
Taylor Instrument Companies, Rochester, X. Y.) 

air becomes more humid. Sometimes heat or a draft of com- 
pressed air will remove odors from solid surfaces where mere 
ventilation will not. 

Testing Air. — The air in living rooms which is not being 
changed with sufficient frequency is likely to be odorous and 
it is not difficult to detect this with the senses upon entering 
a close or stuffy room. The test for the amount of carbon 
dioxide in the air will also indicate whether the air is fresh 
or used. The temperature may be read directly from a ther- 
mometer. 



328 



HYGIENE: DENTAL AND GENERAL 



But we must know the relative humidity of air as well as 
its temperature in order to know whether it is properly con- 
ditioned for the body. Relative humidity is expressed in 
terms of per cent saturation. When the air is completely 
saturated with moisture we have a mist or fog. At 68° F. 
the optimum humidity is about 50 per cent. 

The body is sensitive to the dryness of the air because the 
drier the air the greater the evaporation of moisture. It is 
this principle that is used in determining relative humidity. 
If the bulb of an ordinary thermometer is wrapped in a moist 
cloth, evaporation will take place from the cloth and the 
thermometer will be cooled, registering a lower temperature 




Fig. 50. — Sling psychrometcr. (Courtesy of the Taylor Instrument Companies, 

Rochester, N. Y.) 



than the ordinary thermometer in the same room. The drier 
the air, the greater the rate of evaporation, the greater will be 
the difference between the dry bulb and wet bulb readings. 
The movement of air also affects the rate of evaporation ; but 
evaporation approaches its maximum rate when the air is mov- 
ing at about four miles per hour, so that if the wet bulb 
thermometer is swung in the air with a free arm motion the 
minimum reading can be obtained in a few moments, 



VENTILATION. HEATING AND LIGHTING 



323 



The Sling* Psychrometer. — An instrument in common use 
for testing the dryness of air is the sling psychrometer which 
consists of a dry bulb thermometer and a wet bulb thermom- 
eter attached to a solid frame which can be rotated in the air. 
The instrument is swung until the minimum reading is ob- 
tained on the wet bulb thermometer and the relative humidity 
is obtained by comparing the difference in temperatures with 
a set of standard tables. From these tables it is possible to 
obtain the relative humidity, the number of grams of moisture 
in the air and the dew point for the air having its dry and 
wet bulb temperatures recorded. 




Fig. 51. — Hygrodeik showing the chart from which the condition of the air 
may be read directly. This is the most satisfactory instrument for telling mois- 
ture content quickly. (Courtesy of the Taylor Instrument Companies, Rochester, 
N. Y.) 



The Hygrodeik. — This instrument has a dry and a wet 
bulb thermometer placed on the two sides of a graphic chart 
in such a way that the approximate percentage saturation, 
grains of water per cubic foot, and dew point may be read 
directly from the chart by comparing the temperatures of 
the two thermometers. A pointer swings across the chart be- 
tween the thermometers and the desired readings may be ob- 
tained by placing it over the intersection of the two lines 
which connect the thermometer readings. 



330 HYGIENE: DENTAL AND GENERAL 

The Polymeter. — Various instruments are made which indi- 
cate roughly the relative humidity by showing the effect of 
moisture in contracting or expanding some substance like 
horse hairs. The horse hair is usually run from the top of 
the instrument to a shaft connecting with a dial at the base. 
If these instruments are kept in proper condition the dial 
will roughly indicate the amount of moisture in the air, that 
is, with an accuracy of perhaps 1° to 5°. But in order that 
they remain in good condition they should be dipped in water 
every day or at least every few days. 

The Comfort Meter. — Dr. Hill has developed a new instru- 
ment for indicating the quality of the air which does away 
with the difficulty of trying to combine the two factors of 
temperature and humidity. This is a spirit thermometer 
graduated from 95° to 100° F. It is heated to 100° and the 
time taken to fall to 95° is registered. Without moisture this 
thermometer records of the effect of the temperature and 
motion of the air; when a cloth saturated with water is 
wrapped around the bulb it also takes account of the effect 
of humidity. It will be seen that this instrument when mois- 
tened at 100° F. closely simulates the body, and the cooling 
effect of the air upon a moist warm body at any temperature 
can thus be readily determined. The instrument is calibrated 
and the constant factor is written upon the back. By divid- 
ing the time in seconds by the constant factor, one obtains the 
loss of heat per square centimeter per second in terms of 
milli-calories. The wet bulb should show not less than 18 
milli-calories per second and the dry bulb not less than 6. 

VENTILATING AND HEATING 

The problem of ventilation is to supply clean air, free from 
bacteria and dust, at the proper temperature and with the 
suitable amount of moisture. To ventilate we must renew 
the air in a room but in order to secure air which is properly 
conditioned we must often heat or cool, and moisten or dry 
the air in addition. 



VENTILATION, HEATING AND LIGHTING 331 

Merely because we have assigned new causes for the dis- 
agreeable effects which have always been recognized as the 
result of poor air, we must not forget that these ill effects 
still persist. Properly conditioned air must always be sup- 
plied and in a suitable quantity and standards of air space 
in different kinds of workrooms are still useful, although we 
should remember that the rate of change of air is more im- 
portant than the size of the workroom. 

The standards set by a committee of the American Society 
of Heating and Ventilation in 1915, prescribe for a theatre, 
a floor space per person of 6 square feet, a cubic space of 90 
cubic feet, and an air spply of 1,200 cubic feet per hour. In 
a workshop the floor space should be increased usually to 25 
square feet, the cubic space to 250 cubic feet, and the hourly 
air supply to 1,500 cubic feet per person (the amount of air 
required for an ordinary gas burner). The air should be of 
a temperature between 60° and 72° F. The distribution 
should maintain the proper temperature without uncomfort- 
able drafts or any draft lower than 60° F. For temperatures 
above 55° F. the most comfortable percentage humidity may 
be obtained from the formula R = 316 - 4T, where T = the 
temperature of the room and R = the corresponding relative 
humidity. 

The air should be free from unpleasant odors and reason- 
ably free from dust which of itself is more or less irritating 
and is usually germ laden. Mechanical exhaust systems are 
needed in many workrooms to keep the air free from dust, 
while air washing is necessary in some localities to secure a 
satisfactory supply. 

Natural Ventilation. — Ventilation may be either natural or 
artificial. By natural ventilation we mean the replacing of 
air inside a building by the outside air which works its way 
of its own accord through the wall and through openings to 
the outside. Even solid walls allow for the passage of a good 
deal of air and much more enters through open windows. 
ventilating flues, or chimneys, cracks or crevices in the walls. 



332 HYGIENE: DENTAL AND GENERAL 

under doors and around windows. There are numerous me- 
chanical appliances which furnish openings through walls 
or windows and assist in the interchanging of inside and out- 
side air. Sometimes this exchange of air is assisted by aspirat- 
ing or withdrawing the air from within by means of the 
natural draft of a flue or chimney augmented by a heater. 
The amount of leakage of air in a building depends on the 
ratio of the cubic contents of the building to the exposed sur- 
face, the tightness of doors, windows, etc., and the condition 
of the walls. In general it is assumed that the leakage amounts 
to one change of air per hour. That is, an amount of air 
equal to the cubical contents of a frame building will pass 
through the walls each hour and an equal volume of air must 
be heated to replace the loss. The air will oftentimes be 
changed two times per hour by spontaneous ventilation. 

The size of the room as well as the number of people in the 
room influences the rate at which the air should be changed. 
The number of changes of air which take place under direct 
heating in buildings is given below. 

NUMBER OF TIMES AIR CHANGES PER HOUR 

Residences Halls 3; sitting-rooms 2 

Stores First story 2 to 3; 2nd story 1% to 2 

Offices First story 2 to 2%; 2nd story iy 2 to 2 

Churches and Halls % to 2 

Large rooms with 

small exposure % to 1 

Artificial or Mechanical Ventilation. — For large buildings 
such as halls, churches, business establishments and factories, 
the change of air through natural processes is not sufficient 
and some mechanical system of ventilation is adopted. This 
may be one of three types: (1) the exhaust or vacuum sys- 
tem by which air is withdrawn from the room by means of 
suction fans, (2) the plenum system by which air is forced 
into the room by fans or (3) the combined method which 
forcibly brings air into the room and forcibly exhausts it, 
combining both of the above systems. 



VENTILATION", HEATING AXD LIGHTIXG 333 

There are various ways of introducing and removing air 
from a room, but in general it may be said that in buildings 
of moderate size such as residences, office-buildings, school- 
rooms and factories, where the building is cut up into rooms 
not over fifty feet square, the intake ducts should be in the 
side walls near the top of the room from eight to ten feet 
above the floor and should discharge the air with a velocity 
not exceeding 6 feet per second so that the drafts will not be 
felt. Exit ducts should be in the side walls near the floor. 
By bringing the heated air in at the top of the room its 
velocity is gradually dissipated and by the time the incoming 
air has descended to the breathing level no draft should be 
felt. The opening of a register should be from 0.66 to 0.75 of 
the area of the opening in the duct into which the register fits. 

In modern factories the air is heated to a temperature of 
from 90° -140° and is forced into the building by fans. This 
air after supplying wall losses by its loss in temperature is 
taken back to the fan at 60° -70° and is then drawn through 
the heater, heated again to the higher temperature and forced 
back into the factory. The air in the factory is thus put un- 
der a slight pressure and any leakage of air is outward, 
therefore a small amount of outside air must be constantly 
added before the air passes through the heater. 

There are various ways of distributing the air sent in by 
the fans. The most common method is by ducts located from 
8 to 18 feet above the floor. It is also done by means of 
hollow pilasters in the sides of the long distributing ducts 
which extend the entire length of the building. The velocity 
of the discharged air varies from 3 to 50 feet per second 
depending on the size of the room. Where there are numer- 
ous outlets and low velocities, the combined area of the air 
inlets should exceed the discharge area of the fan by 25 per 
cent. 

The Importance of Moisture.— It may be demonstrated 
that the air in a room at 65° F. and 50-55% relative humidity, 
actually feels warmer than that of a room which is maintained 



334 HYGIENE: DENTAL AND GENERAL 

at 70-75° F. and 30% relative humidity. This is due to the 
fact that the sensation of heat or cold felt by the body, or 
the "sensible temperature" is not indicated by the tempera- 
ture of the dry bulb thermometer, but more closely cor- 
responds to the temperature indicated by the wet bulb ther- 
mometer. From this it is evident that a higher temperature 
is maintained in our buildings than would be required if ar- 
rangements were made for maintaining the proper relative 
humidity. 

If a room feels cold at 68° F. it is because the humidity 
is too low. The amount of moisture a cubic foot of air will 
hold depends entirely upon the temperature. The lower the 
temperature of the air, the less moisture it is capable of 
holding. Air at 70° F. will, if saturated, hold 8 grains of 
moisture per cubic foot. Air at 0° F. will hold practically 
0.48 grains per cubic foot at saturation. The average rela- 
tive humidity during winter is about 70% ; hence air at 0° F. 
and 70% relative humidity contains 0.34 grains of moisture 
per cubic foot. If this air is drawn from outdoors into a 
building and heated to 70° F. the absolute humidity or the 
weight of moisture per cubic foot will remain the same as be- 
fore, but the relative humidity is now reduced to about 4%. 
Such air is drier than that of the most arid region. 

Dry furnace air is therefore likely to cause excessive evap- 
oration and give one a chilly feeling. For living rooms 
and offices the humidity may be increased by plants, or by 
porous dishes, like flower-pots, containing water or by plac- 
ing a dish of water or a Avet towel on or near the radiator. 
It is evident that fuel can be saved by maintaining air of a 
reasonably high humidity. 

Air Washing and Humidifying'. — Although the humidity 
may be secured by simple devices in small rooms, more in- 
tensive methods must be used for large buildings. The types 
of air- washers and humidifiers in ordinary use are the "moist 
sheet"; "film of water"; and the "spray or rain" types. 
These are all modifications of one. another and in all the 
water is forced through small openings in pipes so that a 



VENTILATION, HEATING AND LIGHTING 335 

sheet of water is formed, through which the air must pass. 
The water is discharged through perforated pipes extending 
across the top of chambers, these pipes discharging against a 
deflector. 

In the general method of washing and conditioning air it 
is first drawn through the washer by means of a fan. The 
water carried mechanically by the air is separated by means 
of eliminator plates; then the saturated air is heated by 
heater-coils to the desired temperature. By regulating the 
temperature of the saturated air entering the heater, the hu- 
midity of the heated air may be made any desired amount. 
By the use of by-passes under the heating coils, mixing damp- 
ers, thermostats, etc., it is possible to supply a constant vol- 
ume of pure air to the rooms and to regulate the humidity of 
this air. Tempering coils are important where the incoming 
air is apt to go below 32° F. especially where all the air 
handled is taken from out of doors. 

The washing of air is often almost as important as the hu- 
midifying. It is necessary to use the outside air for ventila- 
tion and this air is taken from the lower levels where the 
amounts of dust, bacteria, and noxious gases are most concen- 
trated. Whipple has shown that when street air is passed 
through a washer it requires but a few hours for the water 
to become like sewage in appearance and analysis. Air drawn 
from the rooms, purified and reheated is up to all standards 
and the cost of fuel necessary to heat the air is considerably 
reduced. 

Cooling Air. — To cool air and at the same time to reduce 
the amount of moisture, it becomes necessary to work with 
water at a temperature lower than can ordinarily be obtained 
from either driven wells or from city mains. Air cooled by 
ice is unsatisfactory as it is difficult to cool it sufficiently to 
deposit flic excess moisture and the slightly cooled air is likely 
to have a high relative humidity. 

The only satisfactory method of air cooling is by the use 
of refrigerating machines, such as ammonia compression or 
absorption machines by which the temperature may be re- 



336 HYGIENE: DENTAL AND GENERAL 

ducecl enough to cause a precipitation of the excess of mois- 
ture contained in the air. When air is cooled by this method 
a fan draws the air from the room and sends it through a 
sheet of cold brine which is continually cooled by an ammonia 
outfit. This brine is sprayed into the air as is the water in 
an air washing machine. 

In other cases the air may be sent through a cooler con- 
taining the coils of an ammonia machine. To keep the coils 
from becoming covered with frost, brine is allowed to trickle 
over them. This brine washes the air to some .extent. It 
is very important that the brine be of sufficient strength to 
prevent freezing. 

Air taken in from the room may be cooled, de-humidified 
and sent back or some of the outside air of higher temperature 
and humidity may be mixed with cooled air in proper pro- 
portion to give the final temperature and humidity desired. 
In general it is necessary to cool air to 45° or 50° in order to 
get rid of the excess moisture, and it is then necessary to 
heat this air again to 70°. The hot moist air on its way from 
the room to the cooler may be made to transfer some of its 
heat to the cold, de-humidified air on its way back to the room. 

The Economic Value of Good Ventilation. — Industries have 
found that it is particularly important to remove dust, gases 
and fumes which irritate the breathing passages of the worker 
and cause congestion or predispose the individual to infectious 
diseases. But even where dusts are not present the proper 
regulation of temperature and humidity has an important 
bearing upon health and efficiency. Dr. Winslow has shown 
that under the same conditions of work 6 per cent more type- 
writing is performed at 68° than at 75°. In more vigorous 
physical work such as ordinary industrial activities, the 
amount accomplished at 68° is 15% greater than that accom- 
plished at 75°. In the work of the New York Commission on 
Ventilation it was shown that the respiratory diseases among 
school children in a group of rooms averaging 69° in tempera- 
ture were 50 per cent in excess of similar respiratory diseases 
among groups of children from school rooms whose tempera- 



VENTILATION, HEATING AND LIGHTING 337 

tures averaged only 66°. It is a cardinal rule that the tem- 
perature of living and work places should never exceed 68° 
and with proper humidity a healthy individual will not be 
uncomfortable at this temperature. Each work room should 
have a thermometer and some arrangement should occasion- 
ally be made to determine the humidity. 

Physicians feel that out of door air is better than inside 
air for invalids and consumptives, even though the inside air 
is properly conditioned. This benefit from being out of doors 
may be due to sunlight or it may be due to the constantly 
varying temperature of the outdoor air which doubtless serves 
as a stimulus and tonic to the system. 

LIGHTING 

Good lighting is important in a variety of ways. Direct 
sunlight is a disinfectant and it has been found to increase the 
peripheral lymphocytosis in the body. Its value in treating 
tuberculosis of the skin, for example, has been well demon- 
strated. It should be allowed to enter the home and the work 
place as much as possible but it should be prevented from 
shining directly in the face of the worker. 

Outdoor life is the normal condition to which man has be- 
come accustomed throughout the process of evolution. Under 
these conditions the light comes from a luminous body above 
and very little light is reflected from the green or brown of 
the earth, so that the upper part of the retina is not accus- 
tomed to a strong stimulation. If the person looks up at the 
sun directly the stimulation is excessive and painful. This 
suggests the ideal condition for artificial lighting. Strong 
light should not be thrown directly into the eyes from below. 

Man has acquired great power in adjusting the eyes to the 
effects of bright daylight and darkness. This is clone by 
varying the size of the pupil through the muscular contrac- 
tion of the iris. Flickering light causes the eye to attempt a 
rapid series of these adjustments, a continual contraction and 
expansion of this muscle resulting in eye strain, nervousness 
and fatigue. 



338 HYGIENE : DENTAL AND GENERAL 

Ideal lighting provides sufficient and steady illumination 
at the point of work and the lighting should be judged not by 
the brightness of the lamps but by the illumination at the 
point where the work is done. Dark objects require more il- 
lumination than light objects. 

Office Lighting. — Ample window space is usually provided 
in front of the dentist 's chair but sufficient care is not always 
taken to provide adequate means of regulating the lighting 
under different weather conditions by means of shades and 




Fig. 52. — A foot candlemeter which is portable and easy to use in measuring light 
intensities. (Courtesy of the National Lamp Works, Cleveland, Ohio.) 

curtains. These should be so arranged that they can be made 
to cover either the lower or the upper part of the windows and 
should be of light green or yellow material. 

The artificial lighting should be indirect in order to avoid 
glare either in the eyes of the operator or the patient. In- 
direct lighting may be provided by the use of translucent 
material or by a reflector throwing the light up to the ceiling. 
Much light is lost by the latter type of lighting however and 
more efficiency can be secured by the use of a ridged glass 
which splits and divides the rays of light. In any case the 
artificial light should be steady and not flickering. 



APPENDIX A 

THE CONTEOL OF COMMUNICABLE DISEASES 

Report of The American Public Health Association 

Committee on Standard Regulations, Appointed 

in October, 1916.* 

In the following report the terms used are first defined. 
Each disease is briefly described with regard to the infective 
agent, the source of infection, the mode of transmission, the 
incubation period, and the period of communicability. Fol- 
lowing this are given the methods of control — first, those affect- 
ing the individual patient and his immediate environment, 
and second, general measures bearing upon the control or 
prevention of the disease in question. 

Inasmuch as the laws under which various boards and de- 
partments of health operate require differences in the legal 
phraseology of rules, regulations, or sections of sanitary codes 
dealing with the control of communicable diseases the com- 
mittee has refrained from preparing formal regulations under 
each disease. As the report is'at present submitted any health 
officer, board of health, or legislative body having the power 
to make rules or regulations or pass sections of sanitary codes 
dealing with the control of communicable diseases can, by 
reference to the description of the disease and recommenda- 
tions for methods of control herewith proposed, easily prepare 
the necessary text upon which the educational and adminis- 
trative acts of the health officer will be based. The list of 
diseases considered by the committee and herewith reported 
upon includes those given in the Public Health Reports, Vol. 
30, No. 27, July 2, 1915, of the Public Health Service in "A 
Model State Law for Morbidity Reports." 



*Reprint from the Public Health Reports, vol. 32, No. 41. Oct. 12, 1917, pp. 
1706-1733. Used with permission of the American Public Health Assn. 

339 



340 



HYGTENE: DENTAL AND GENERAL 



The committee is indebted for expert opinion and critical 
comment upon its tentative conclusions to Dr. Simon Flexner, 
Dr. William H. Park, Prof. Theobald Smith, and Dr. Bertram 
H. Waters, and acknowledgment of their contributions to the 
report in its present form is herewith gratefully expressed. 

Dr. Haven Emerson, Chairman. 
Robert 1ST. Hoyt. 
Dr. F. M. Meader. 
Dr. J. C. Perry. 
C. E. A. Winslow. 



List of Diseases 



Actinomycosis. 

Acute infectious conjunctivitis. 
Ankylostomiasis (hookworm). 
Anthrax. 

Cerebrospinal meningitis (epi- 
demic). 
Chicken pox. 
Cholera. 
Dengue. 
Diphtheria. 
Dysentery (amebic). 
Dysentery (bacillary). 
Favus. 

German measles. 
Glanders. 
Gonorrhea. 
Leprosy. 
Malaria. 
Measles. 
Mumps. 



Paratyphoid fever. 

Plague. 

Pneumonia (acute lobar). 

Poliomyelitis. 

Rabies. 

Rocky Mountain spotted or tick 
fever. 

Scarlet fever. 

Septic sore throat. 

Smallpox. 

Syphilis. 

Tetanus. 

Trachoma. 

Trichinosis. 

Tuberculosis (pulmonary). 

Tuberculosis (other than pulmon- 
ary). 

Typhoid fever. 

Typhus fever. 

Whooping cough. 

Yellow fever. 



The committee adopted the following definitions of terms : 

1. Carrier. — A person who, without symptoms of a communicable 
disease, harbors and disseminates the specific microorganisms. 

2. Cleaning. — This term signifies the removal, by scrubbing and wash- 
ing, of organic matter on which and in which bacteria may find favor- 
able conditions for prolonging life and virulence; also the removal by 
the same means of bacteria adherent to surfaces. 



THE CONTROL OF COMMUNICABLE DISEASES 341 

3. Contact. — A " contact " is any person or animal known to have 
been sufficiently near to a human infected person or animal to have been 
exposed to transfer of infectious material directly, or by articles freshly 
soiled "with such material. 

4. D dousing. — By delousing is meant the process by which a person 
and his personal apparel are treated so that neither the adults nor the 
eggs of Pediculus corporis or Pediculus capitis survive. 

5. Disinfection. — By this is meant the destroying of the vitality of 
pathogenic microorganisms by chemical or physical means. 

When the word concurrent is used as qualifying disinfection, it in- 
dicates the application of disinfection immediately after the discharge 
from the body of an infected person, of infectious material, or the soil- 
ing of articles with such infectious discharges. 

When the word terminal is used as qualifying disinfection, it indicates 
the process of rendering the personal clothing and immediate physical 
environment of the patient free from the possibility of conveying the 
infection to others, at the time when the patient is no longer a source of 
infection. 

6. Education in personal cleanliness. — By this phrase it is intended 
to include all the various means available to impress upon all members 
of the community, young and old, and especially when communicable 
disease is prevalent or during epidemics, by spoken and printed word, 
and by illustration and suggestion, the necessity of : 

(1) Washing the body daily with soap and water. 

(2) Washing hands in soap and water after voiding bowels or bladder 
and always before eating. 

(3) Keeping hands and unclean articles, or articles which have been 
used for toilet purposes by others away from mouth, nose, eyes, ears, and 
vagina. 

(4) Avoiding the use of common or unclean eating, drinking, or 
toilet articles of any kind, such as towels, handkerchiefs, hair brushes, 
drinking cups, pipes, etc. 

(5) Avoiding direct exposure to the spray from the noses and mouths 
of people who cough or sneeze, or laugh and talk loudly, with wide open 
mouth, or in explosive manner. 

7. Fumigation* — By fumigation is meant a process by which the 
destruction of insects, as mosquitoes and body lice, and animals, as. rats, 
is accomplished by the employment of gaseous agents. 



* Author's Note: This definition of fumigation applies throughout the follow- 
ing report and was doubtless arbitrarily adopted because fumigation is no longer 
regarded as effective for killing the germs of disease. Fumigation is still under- 
stood by the general public, however, as an attempt at disinfection by means of 
a gas. 



342 HYGIENE: DENTAL AND GENERAL 

8. Isolation * — By isolation is meant the separating of persons suf- 
fering from communicable disease, or carriers of the infecting organ- 
ism, from other persons, in such places and under such conditions as will 
prevent the direct or indirect conveyance of the infectious agent to sus- 
ceptible persons. 

9. Quarantine.* — By quarantine is meant the limitation of freedom 
of movement of persons or animals who have been exposed to commu- 
nicable disease for a period of time equal to the incubation period of the 
disease to which they have been exposed. 

10. Renovation. — By renovation is meant, in addition to cleansing, 
such treatment of the walls, floors, and ceilings of rooms or houses as 
may be necessary to place the premises in a satisfactory sanitary condi- 
tion. 

11. Report of a disease. — By report of a disease is meant the notifi- 
cation to the health authorities, and, in the case of communicable disease 
in animals, also to the respective departments of agriculture who have 
immediate jurisdiction, that a case of communicable disease exists in a 
specified person or animal at a given address. 

12. Susceptibles. — A susceptible is a person or animal who is not 
known to have become immune to the particular communicable disease 
in question by natural or artificial process. 

The items considered necessary for presentation by the 
committee with regard to each disease are the following: 

1. Infective agent. 

2. Source of infection. 

3. Mode of transmission. 

4. Incubation period. 

5. Period of communicability. 

6. Methods of control. 

(A) The infected individual and his environment: 

1. Eecognition of the disease. 

2. Isolation. 

3. Immunization. 

4. Quarantine. 

5. Concurrent disinfection. 

6. Terminal disinfection. 

(B) General measures. 

(C) Epidemic measures (occasionally require separate mention). 



*In view of the various ambiguous and inaccurate uses to which the words 
isolation and quarantine are not infrequently put, it has seemed best to adopt 
arbitrarily the word isolation as describing the limitation put upon the movements 
of the known sick or "carrier" individual or animal, and the word quarantine the 
limitations put upon exposed or "contact" individuals or persons. 



THE CONTROL OF COMMUNICABLE DISEASES 343 

Actinomycosis 

1. Infective agent: Actinomyces bovis. 

2. Source of infection : The nasal and bowel discharges, and the in- 

fected material from lesions in human and animal cases of the 
disease. Uncooked meat from infected animals may serve as a 
source of infection. 

3. Mode of transmission: By contact with the discharges or with articles 

freshly soiled with the discharges from animal or human cases. 

4. Incuoation period: Unknown. 

5. Period of communicaoility : As long as open lesions remain, as proved 

by the presence of the infective agent on microscopic or cultural 
tests. 

6. Methods of control: 

(A) The infected individual and his environment — 

1. Recognition of the disease — Clinical symptoms, con- 

firmed by microscopic examination of discharges from 
the lesions. 

2. Isolation — None, provided the patient is under adequate 

medical supervision. 

3. Immunization — None. 

4. Quarantine — None. 

5. Concurrent disinfection — Of discharges from lesions and 

articles soiled there with. 

6. Terminal disinfection — By thorough cleaning. 

(B) General measures — 

1. Inspection of meat, with condemnation of carcasses, or 

infected parts of carcasses, of infected animals. 

2. Destruction of known animal sources of infection. 

Acute Infectious Conjunctivitis 

(Not including trachoma) 

(This title to replace the terms gonorrheal ophthalmia, ophthalmia 
neonatorum, and babies' sore eyes.) 

1. Infectious agent: The gonococcus »,r sonic member of a group of 

pyogenic organisms, including the hemoglobinophilic bacilli. 

2. Source of infection: Discharges from conjunctivae, or adnexa, of geni 

tal mucous membranes of infected persons. 

3. Modes of transmission: Contact with an infected person or with ar- 

ticles freshly soiled with discharges of such person. 



344 HYGIENE: DENTAL AND GENERAL 

4. Incubation period: Irregular, but usually 36 to 48 hours. 

5. Period of communicability : During the course of the disease and until 

the discharges from the infected mucous membranes have ceased. 

6. Methods of control: 

(A) The infected individual and his environment — 

1. Recognition of the disease — Clinical symptoms, confirmed 

where possible by bacteriological examination. 

2. Isolation — None, provided the patient is under adequate 

medical supervision. 

3. Immunization — None. 

4. Quarantine — None. 

5. Concurrent disinfection — Disinfection of conjunctival dis- 

charges and articles soiled therewith. 

6. Terminal disinfection — Thorough cleansing. 

(B) General measures — 

1. Enforcement of regulations forbidding the use of com- 

mon towels and toilet articles. Education as to per- 
sonal cleanliness. 

2. Use of silver nitrate or some similar solution in the eyes 

of the new born. 

Anchylostomiasis 

(Hookworm) 

1. Infectious agent. — Anchylostoma (Necator amerieanus). 

2. Source of infection. — Feces of infested persons. Infection generally 

takes place through the skin, occasionally by the mouth. 

3. Mode of transmission. — The larval forms pierce the skin, usually of 

the foot, and passing through the lymphatics to the vena cava and 
the right heart, thence in the blood stream to the lungs, they pierce 
the capillary walls and pass into the alveoli. Then they pass up the 
bronchi and trachea to the throat, whence they are swallowed and 
finally lodge in the small intestine. Also by drinking water contain- 
ing larvae, by eating soiled food, by hand to mouth transmission of 
the eggs or larvae from objects soiled with infected discharges. 

4. Incubation period. — Seven to 10 weeks. 

5. Period of communicability. — As long as the parasite or its ova are 

found in the bowel discharges of an infected individual. Contami- 
nated soil remains infective for five months in the absence of freez- 
ing. 

6. Methods of control: 

(A) The infected individual and his environment — 

1. Recognition of the disease — Microscopic examination of 
bowel discharges. 



THE CONTROL OF COMMUNICABLE DISEASES 345 

2. Isolation — None. 

3. Immunization — None. 

4. Quarantine — None. 

5. Concurrent disinfection — Sanitary disposal of bowel dis- 

discharges. 

6. Terminal disinfection — None. 

7. Treatment — Appropriate treatment of infected individual 

to rid the intestinal canal of the parasite and its ova. 
(B) General measures — 

1. Education as to dangers of soil pollution. 

2. Prevention of soil pollution by installation of sanitary 

disposal systems for human discharges. 

3. Personal prophylaxis by cleanliness and the wearing of 

shoes. 

Anthrax 

1. Infectious agent. — Bacillus anthracis. 

2. Source of infection. — Hair, hides, flesh, and feces of infected animals. 

3. Mode of transmission. — Inoculation as by accidental wound or scratch, 

inhalation of spores of the infectious agent, and ingestion of in- 
sufficiently cooked infected meat. 

4. Incubation period. — Within seven days. 

.">. Period of communicability. — During the febrile stage of the disease 
and until lesions have ceased discharging. Infected hair and hides 
of infected animals may communicate the disease for many months 
after slaughter of the animal, and after curing of hide, fur, or hair, 
unless disinfected. 

6. Methods of control: 

(A) The infected individual and his environment — 

1. Recognition of the disease — Clinical symptoms, con- 

firmed by bacteriological examination. 

2. Isolation of the infected individual until the lesions have 

healed. 

3. Immunization — None. 

4. Quarantine — None. 

5. Concurrent disinfection of the discharges from lesions 

and articles soiled therewith. 

6. Terminal disinfection — Thorough cleaning. 

(B) General measures — 

1. Animals ill with a disease presumably anthrax should be 
placed immediately in the care of a veterinary surgeon. 
Proved animal cases of the disease should be killed 
promptly ami the carcasses destroyed, preferably by fire. 



346 HYGIENE: DENTAL AND GENERAL 

2. Isolation of all animals affected with the disease. 

3. Immunization of exposed animals under direction of 

Federal or State Department of Agriculture. 

4. Postmortem examinations should be made only by a vet- 

erinary surgeon, or in the presence of one. 

5. Milk from an infected animal should not be used during 

the febrile period. 

6. Control and disinfection of effluents and trade wastes 

and of areas of land polluted by such effluents and 
wastes from factories or premises, where spore-infected 
hides or other infected hide and hair products are 
known to have been worked up into manufactured ar- 
ticles. 

7. A physician should be constantly employed by every 

company handling raw rides, or such companies should 
operate under the direct supervision of a medical rep-" 
resentative of the health department. 

8. Every employee handling raw hides, hair, or bristles who 

has an abrasion of the skin should immediately report 
to a physician. 

9. Special instruction should be given to all employees 

handling raw hides in regard to the necessity of per- 
sonal cleanliness. 

10. Tanneries and woolen mills should be provided with 

proper ventilating apparatus so that dust can be 
promptly removed. 

11. Disinfection of hair, wool, and bristles of animals origi- 

nating in known infected centers before they are used 
or assorted. 

12. The sale of hides from an animal infected with anthrax 

should be prohibited. A violation of this regulation 
should be immediately reported to the State commis- 
sioner of agriculture, by telegram, stating the time, 
place, and purchaser to whom the hide was sold. The 
report should also be sent to the person purchasing the 
hide. Carcasses should be disposed of under the super- 
vision of the State department of agriculture. The in- 
spection and disinfection of imported hides are under 
the supervision of the United States Bureau of Animal 
Industry. In the event that infection is introduced the 
State agricultural authorities have jurisdiction over in- 
fected animals and the local or State health authorities 
have jurisdiction over infected persons. 



THE CONTROL OF COMMUNICABLE DISEASES 34.7 

Cerebrospinal Meningitis 

1. Infective agent: Diplococcus intracellularis (the meningococcus). 

2. Source of infection: Discharges from the nose and mouth of infected 

persons. Clinically recovered cases, and healthy persons who have 
never had the disease but have been in contact with cases of the dis- 
ease or other carriers, act as carriers and are commonly found, es- 
pecially during epidemics. Such healthy carriers are not uncom- 
monly found independent of epidemic prevalence of the disease. 

3. Mode of transmission : By direct contact with infected persons and 

carriers, and indirectly by contact with articles freshly soiled with 
the nasal and mouth discharges of such persons. 

4. Incubation period: Two to ten days, commonly seven. Occasionally 

for longer periods when a person is a carrier for a time before de- 
veloping the disease. 

5. Period of commimicability : During the clinical course of the disease 

and until the specific organism is no longer present in the nasal and 
mouth discharges of the patient. The same applies to healthy car- 
riers so far as affects persistence of infectious discharges. 

6. MeiJwds of control: 

(A) The infected individual and his environment — 

1. Recognition of the disease — Clinical symptoms, confirmed 

by the microscopic and bacteriological examination of 
the spinal fluid, and by bacteriological examination of 
nasal and pharyngeal secretions. 

2. Isolation of infected persons and carriers until the naso- 

pharynx is free from the infecting organism, or, at the 
earliest, until one week after the fever has subsided. 

3. Immunization may prove of value. Immunization by the 

use of vaccines still in the experimental stage. 

4. Quarantine — None. 

5. Concurrent disinfection of discharges from the nose and 

mouth and of articles soiled therewith. 

6. Terminal disinfection — Cleaning. 

(B) General measures — 

1. Search for carriers among families and associates of rec- 

ognized cases by bacteriological examination of pos- 
terior nares of all contacts. 

2. Education as to personal cleanliness and necessity of 

avoiding contact and droplet infection. 

3. Prevention of overcrowding such as is common in living 

quarters, transportation conveyances, working places, 
and places of public assembly in the civilian population, 
and in inadequately ventilated closed quarters in bar- 
racks camps, and ships among military units. 



348 HYGIENE : DENTAL AND GENERAL 

Chicken Pox 

1. Infectious agent: Unknown. 

2. Source of infection :The infectious agent is presumably present in the 

lesions of the skin and of the mucous membranes; the latter appear- 
ing early and rupturing as soon as they appear, render the disease 
communicable early, that is, before the exanthem is in evidence. 

3. Mode of transmission: Directly from person to person; indirectly 

through articles freshly soiled by discharges from an infected in- 
dividual. 

4. Incubation period: Two to three weeks. 

5. Period of communicability : Until the primary scabs have disappeared 

from the mucous membranes and the skin. 

6. Methods of control: 

(A) The infected individual and his environment — 

1. Eecognition of the disease — Clinical symptoms. The dif- 

ferential diagnosis of this disease from smallpox is im- 
portant, especially in people over 15 years of age. 

2. Isolation — Exclusion of patient from school, and preven- 

tion of contact with nonimmune persons. 

3. Immunization — None. 

4. Quarantine — None. 

5. Concurrent disinfection of articles soiled by discharges 

from lesions. 

6. Terminal disinfection — Thorough cleaning. 

(B) General measures — None. 

Cholera 

1. Infectious agent: Vibrio cholera?. 

2. Source of infection: Bowel discharges and vomitus of infected per- 

sons, and feces of convalescent or healthy carriers. Ten per cent 
of contacts may be found to be carriers. 

3. Mode of transmission: By food and water polluted by infectious 

agent; by contact with infected persons, carriers, or articles freshly 
soiled by their discharges; by flies. 

4. Incubation period: One to five, usually three, days, occasionally longer 

if the healthy carrier stage, before development of symptoms, is 
included. 

5. Period of communicability : Usually 7 to 14 days or longer and until 

the infectious organism is absent from the bowel discharges. 

6. Methods of control: 

(A) The infected individual and his environment — 

1. Recognition of the disease — Clinical symptoms, confirmed 
by bacteriological examination. 



THE CONTROL OF COMMUNICABLE DISEASES 349 

2. Isolation of patient in hospital or screened room. 

3. Immunization by vaccination may be of value. 

4. Quarantine — Contacts for five days from last exposure, 

or longer if stools are found to contain the cholera 
vibrio. 

5. Concurrent disinfection — Prompt and thorough disinfec- 

tion of the stools and vomited matter. Articles used by 
and in connection with the patient must be disinfected 
before removal from the room. Food left by the pa- 
tient should be burned. 

6. Terminal disinfection — Bodies of those dying from chol- 

era should be cremated if practicable, or, otherwise, 
wrapped in a sheet wet with disinfectant solution and 
placed in water-tight caskets. The room in which a 
sick patient was isolated should be thoroughly cleaned 
and disinfected. 

(B) General measures — 

1. Bigid personal prophylaxis of attendants by scrupulous 

cleanliness, disinfection of hands each time after han- 
dling patient or touching articles contaminated by de- 
jecta, the avoidance of eating or drinking anything in 
the room of the patient, and the prohibition of those 
attendant on the sick from entering the kitchen. 

2. The bacteriological examination of the stools of all con- 

tacts to determine carriers. Isolation of carriers. 

3. "Water should be boiled, if used for drinking or toilet 

purposes, or if used in washing dishes or food containers, 
unless the water supply is adequately protected against 
contamination or is so treated, as by chlorination, that 
the cholera vibrio can not survive in it. 

4. Careful supervision of food and drink. Where cholera is 

prevalent, only cooked foods should be used. Food and 
drink after cooking or boiling should be protected 
against contamination, as by flies and human handling. 

(C) Epidemic measures — 

Inspection service for early detection and isolation of cases; 
examination of persons exposed in infected centers for 
detection of carriers, with isolation or control of car- 
riers; disinfection of rooms occupied by the sick, and 
the detention, in suitable camps for five days, of those 
desirous of leaving for another locality. Those so de- 
tained should be examined for detection of carriers. 



350 HYGIENE: DENTAL AND GENERAL 

Dengue 

1. Infectious agent: Unknown. 

2. Source of infection: The blood of infected persons. 

3. Mode of transmission: By the bite of infected mosquitoes, probably 

Aedes calopus (perhaps also Culex fatigans). 

4. Incubation period: Four to five days. 

5. Period of communicability : During the febrile stage of the disease. 

6. Methods of control: 

(A) The infected individual and his environment — • 

1. Recognition of the disease — Clinical symptoms. 

2. Isolation — The patient must be kept in a screened room. 

3. Immunization — None. 

4. Quarantine — None. 

5. Concurrent disinfection — None. 

6. Terminal disinfection — None. Upon termination of the 
case, fumigation of the room and house, to destroy mos- 
quitoes. 

(B) General measures — 

Measures directed toward elimination of mosquitoes. Screen- 
ing of rooms. 

Diphtheria 

1. Infectious agent: Bacillus diphtheriae (the Klebs-Loeffler bacillus). 

2. Source of infection ; Discharges from diphtheritic lesions of nose, 

throat, conjunctiva, vagina, and wound surfaces. Secretions from 
the nose and throat of carriers of the bacillus.. 

3. Mode of transmission : Directly by personal contact, indirectly by ar- 

ticles freshly soiled with discharges, or through infected milk or 
milk products. 

4. Incubation period: Usually two to five days, occasionally longer if 

a healthy carrier stage precedes the development of clinical symp- 
toms. 

5. Period of communicaoility : Until virulent bacilli have disappeared 

from the secretions and the lesions. The persistence of the bacilli 
after the lesions have healed is variable. In fully three-quarters 
of the cases they disappear within two weeks. In 95 per cent of 
cases, the bacilli disappear in four weeks. In exceptional cases 
virulent bacilli remain in the throat and discharges for from two to 
six months. 

6. Methods of control : 

(A) The infected individual and his environment — 

1. Recognition of the disease — By clinical symptoms with 
confirmation by bacteriological examination of dis- 
charges. 



THE CONTROL OF COMMUNICABLE DISEASES 351 

2. Isolation — Until two cultures from the throat and two 

from the nose, taken not less than 24 hours apart, fail 
to show the presence of diphtheria bacilli. Isolation may 
be terminated if persistent diphtheria bacilli prove 
avirulent. "Where termination by culture is impracti- 
cable cases may be terminated with fair safety as a rule 
16 days after onset of the disease. 

3. Immunization — Exposed suseeptibles to be promptly im- 

munized by antitoxin. (By suseeptibles is meant such 
individuals as are found to be nonimmune by the 
Schick test, i. e., those who give a positive reaction). 

4. Quarantine — All exposed persons until shown by bacterio- 

logical examination not to be carriers. 

5. Concurrent disinfection of all articles which have been in 

contact with the patient and all articles soiled by dis- 
charges from the patient. 

6. Terminal disinfection — At the end of the illness, thorough 

airing and sunning of the sick room, with cleaning or 
renovation. 
(B) General measures — 

1. Pasteurization of milk supply. 

2. Application of the Schick test to all contacts, and im- 

munization of all suseeptibles. 

3. Application of the Schick test to all children. 

4. Immunization by toxin-antitoxin inoculation of all sus- 

eeptibles. 

5. Determination of presence or absence of carriers among 

contacts, and, so far as practicable, in the community 
at large. 

Dysentery (Amebic) 

1. Infectious agent : Ameba histolytica. 

2. Xourcc of infection: The bowel discharges of infected persons. 

3. Mode of transmission: By drinking contaminated water, and by eat- 

ing infected foods, and by hand to mouth transfer of infected ma- 
terial; from objects soiled with discharges of an infected individual 
or of a carrier; by flies. 

4. Incubation period: Unknown. 

5. Period of commiinicability : During course of disease and until rc- 

peated microscopic examination of stools shows absence of Ameba 
histolytica. 



352 HYGIENE: DENTAL AND GENERAL 

6. Methods of control: 

(A) The infected individual and his environment — 

1. Eecognition of the disease — Clinical symptoms, confirmed 

by microscopic examination of stools. 

2. Isolation — None. 

3. Immunization — None. 

4. Quarantine — None. 

5. Concurrent disinfection of the bowel discharges. 

6. Terminal disinfection — Cleaning. 

(B) General measures — 

1. Boil drinking water unless the supply is known to be free 

from contamination. 

2. Water supply should be protected against contamination 

and supervision should be exercised over all foods eaten 
raw. 

Dysentery (Bacillary) 

1. Infectious agent: Bacillus dysenteriae. 

2. Source of infection: The bowel discharges of infected persons. 

3. Mode of transmission: By drinking contaminated water, and by eat- 

ing infected foods, and by hand-to-mouth transfer of infected ma- 
terial; from objects soiled with discharges of an infected individual 
or of a carrier by flies. 

4. Incubation period: Two to seven days. 

5. Period of communicability : During the febrile period of the disease 

and until the organism is absent from the bowel discharges. 

6. Methods of control: 

(A) The infected individual and his environment — 

1. Eecognition of the disease— Clinical symptoms, confirmed 

by serological and bacteriological tests. 

2. Isolation — Infected individuals during the communicable 

period of the disease. 

3. Immunization — Vaccines give considerable immunity. 

Owing to severe reactions their use is not universal, nor 
should it be made compulsory except under extreme 
emergency. 

4. Quarantine — None. 

5. Concurrent disinfection — Bowel discharges. 

6. Terminal disinfection — Cleaning. 

(B) General measures — 

1. Eigid personal prophylaxis of attendants upon infected 
persons. 



THE CONTROL OF COMMUNICABLE DISEASES 353 

2. Xo milk or food for human consumption should be sold 

from a place occupied by a patient unless the persons 
engaged therein occupy quarters separate from the 
house where the patient is sick, and all utensils used 
are cleaned and kept in a separate building, and under 
a permit from the health officer. 

3. All attendants upon persons affected with this disease 

should be prohibited from having anything to do with 
the handling of food. 

4. Xecessary precautions against flies. 

Favus 

1. Infectious agent: Achorion schoenleinii. 

2. Source of infection : Lesions of skin, particularly on scalp. 

3. Mode of transmission: Direct contact with patient, and indirectly 

through toilet articles. 

4. Incubation period: Unknown. 

5. Period of communicability : Until skin and scalp lesions are all healed. 

6. Methods of control: 

(A) The infected individual and his environment — 

1. Eecognition of the disease — Clinical symptoms confirmed 

by microscopic examination of crusts. 

2. Isolation — Exclusion of patient from school and other 

public places until lesions are healed. 

3. Immunization — None. 

4. Quarantine — None. 

5. Concurrent disinfection — Toilet articles of patient. 

6. Terminal disinfection — Xone. 

(B) General measures — 

1. Elimination of common utensils, such as hair brushes and 

combs. 

2. Provision for adequate and intensive treatment and cure 

of cases of favus at hospitals and dispensaries, to ab- 
breviate the period of infectivity of the patients. 

German Measles 

1. Infectious agent: Unknown. 

2. Source of infection : Secretions of the mouth and possibly of the nose. 

3. Mode of transmission: By direct contact with the patient or with ar- 

ticles freshly Boiled with the discharges from the nose or throat of 
the patient. 

4. Incubation period: From 10 to 21 days. 



354 HYGIENE: DENTAL AND GENERAL 

5, Period of communicauility : Eight days from onset of the disease. 

6. Method of control: 

(A) The infected individual and his environment — 

1. Eeeognition of the disease — Clinical symptoms. 

2. Isolation — Separation of the patient from nonimmune 

children, and exclusion of the patient from school and 
public places for the period of presumed infectivity. 

3. Immunization — None. 

4. Quarantine — None except exclusion of nonimmune chil- 

dren from school and public gatherings, from the elev- 
enth to the twenty-second day from date of exposure 
to a recognized case. 
5. Concurrent disinfection — Discharges from the nose and 
throat of the patient and articles soiled by discharges. 
6. Terminal disinfection — Airing and cleaning. 

(B) General measures — 

None. 

Note. — The reason for attempting to control this disease is that it may be con- 
fused with scarlet fever during its early stages; each person having symptoms of 
the disease should therefore be placed under the care of a physician and the case 
should be reported to the local department of health. 

Glanders 

1. Infectious agent: Bacillus mallei. 

2. Source of infection: Discharges from open lesions of mucous mem- 

branes, or of the skin of human or equine cases of the disease (i. e., 
pus and mucus from the nose, throat, and bowel discharges from 
infected man and horse). 

3. Mode of transmission: Contact with a case or with articles freshly 

soiled by discharges from a human or equine case. 

4. Incuoation period: Unknown. 

5. Period of communicability : Until bacilli disappear from discharges 

or until lesions have healed. 

6. Methods of control : 

(A) The infected individual and his environment — 

1. Eeeognition of the disease — By specific biological reac- 

tions, such as the complement fixation test, the mallein 
test, the agglutination test, or by nonspecific reactions, 
such as the Straus reaction, if confirmed by culture, or 
by identification of the Bacillus mallei, or by autopsy 
of doubtful cases. 

2. Isolation — Human case at home or hospital; for infected 

horses destruction rather than isolation is advised. 



THE CONTROL OF COMMUNICABLE DISEASES 355 

3. Immunization — Xone of established value or generally 

accepted. 

4. Quarantine of all horses in an infected stable until all 

have been tested by specific reaction, and the removal 
of infected horses and terminal disinfection of stable 
have been accomplished. 

5. Concurrent disinfection — Discharges from human cases 

and articles soiled therewith. 

6. Terminal disinfection — Stables and contents where in- 

fected horses are found. 
(B) General measures — 

1. The abolition of the common drinking trough for horses. 

2. Sanitary supervision of stables and blacksmith shops. 

3. Semi-annual testing of all horses by a specific reaction 

where the disease is common. 

4. Testing of all horses offered for sale where the disease 

is common. 

Note. — In this disease, as in all infectious or communicable diseases from 
which both animals and httmans suffer, cases occurring in animals should be re- 
ported to the Department of Agriculture and human cases should be reported to 
the Department of Health, reciprocal notification thereafter to be accomplished 
through official interdepartment channels. 

Gonorrhea 

1. Infectious agent: Gonococcus. 

2. Source of infection: Discharges from lesions of inflamed mucous mem- 

branes and glands of infected persons, viz., urethral, vaginal, cervi- 
cal, conjunctival mucous membranes, and Bartholin's or Skene's 
glands in the female, and Cowper's and the prostate glands in the 
male. 

3. Mode of transmission: By direct personal contact with infected per- 

sons, and indirectly by contact with articles freshly soiled with the 
discharges of such persons. 

4. Incubation period: One to eight days, usually three to five days. 

5. Period of communicability : As long as the gonococcus persists in any 

of the discharges, whether the infection be an old or a recent one. 

6. Methods of control: 

(A) The infected individual and his environment — 

1. Recognition of the disease — Clinical symptoms, confirmed 

by bacteriological examination or scrum reaction. 

2. Isolation — When the lesions are in the genitourinary 

tract, exclusion from sexual contact, and when the 
lesions are conjunctival, exclusion from school or contact 
with children, so long as the discharges contain the in- 
fecting organism. 



356 HYGIENE: DENTAL AND GENERAL 

3. Immunization — None. 

4. Quarantine — None. 

5. Concurrent disinfection — Discharges from lesions and ar- 

ticles soiled therewith. 

6. Terminal disinfection — None. 
(B) General measures — 

1. Education in matters of sexual hygiene, particularly as 

to the fact that continence in both sexes at all ages 
is compatible with health and development. 

2. Provision for accurate and early diagnosis, and treatment 

in hospitals and dispensaries of infected persons with 
consideration for privacy of record and provision for 
following cases until cured. 

3. Repression of prostitution by use of police power and 

control of use of living premises. 

4. Restriction of sale of alcoholic beverages. 

5. Restrictions of advertising of services or medicines for 

the treatment of sex diseases, etc. 

6. Elimination of common towels and toilet articles from 

public places. 

7. Use of prophylactic silver solution in the eyes of the new 

born. 

8. Exclusion of persons in the communicable stage of the 

disease from participation in the preparing and serving 
of food. 

9. Personal prophylaxis should be advised to those who ex- 

pose themselves to opportunity for infection. 

Leprosy 

1. Infectious agent: Bacillus leprae. 

2. Source of infection : Discharges from lesions. 

3. Mode of transmission: By close, intimate, and prolonged contact with 

infected individuals. Flies and other insects may be mechanical 
carriers. 

4. Incubation period: Prolonged, undetermined. 

5. Period of communicability : Infectivity exists throughout the duration 

of the disease. Where good standards of personal hygiene prevail 
this disease is but slightly communicable. 

6. Methods of control: 

(A) The infected individual and his environment — 

1. Recognition of the disease — Clinical symptoms, confirmed 
by bacteriological examination. 



THE CONTROL OF COMMUNICABLE DISEASES 357 

2. Isolation for life in national leprosarium when this is 

possible. 

3. Immunization — None. 

4. Quarantine — None. 

5. Concurrent disinfection — Discharges and articles soiled 

with discharges. 

6. Terminal disinfection — Thorough cleansing of living 

premises of the patient. 
(B) General measures — 

1. Lack of information as to the determining factors in 

the spread and communication of the disease makes any 
but general advice in matters of personal hygiene of no 
value. 

2. As a temporary expedient, lepers may be properly cared 

for in local hospitals, or if conditions of the patient and 
his environment Avarrant, he may be allowed to remain 
on his own premises under suitable regulations. 

Malaria 

1. Infectious agent: The several species of malarial organisms. 

2. Source of infection: The blood of an infected individual. 

3. Mode of transmission : By bite of the infected Anopheles mosquitoes. 

The mosquito is infected by biting an individual suffering from 
acute or chronic malaria. The parasite develops in the body of 
the mosquito for from 10 to 14 days, after which time the sporozoites 
appear in its salivary glands. 
1. Incubation period: Varies with the type of species of infecting or- 
ganism and the amount of infection; usually 14 days in the tertian 
variety. 

5. Petiod of communicability : As long as the malaria organism exists in 

the blood. 

6. Methods of control : 

(A) The infected individual and his environment — 

1. Recognition of the disease — Clinical symptoms, always to 

be confirmed by microscopical examination of the blood. 
Eepeated examinations may be necessary. 

2. Isolation — Exclusion of patient from approach of mos- 

quitoes, until his blood is rendered free from malarial 
parasites by thorough treatment with quinine. 

3. Immunization — None. The administration of prophylac- 

tic doses of quinine should be insisted upon for those 
constantly exposed 1<> infection and unable to protect 
themselves againsl Anopheles mosquitoes. 



358 HYGIENE: DENTAL AND GENERAL 

4. Quarantine — None. 

5. Concurrent disinfection — None. Destruction of Ano- 

pheles mosquitoes in the sick room. 

6. Terminal disinfection — None. Destruction of Anopheles 

mosquitoes in sick room. 
(B) General Measures — 

1. Employment of known measures for destroying larvae of 

anophelines and the eradication of breeding places of 
such mosquitoes. 

2. Blood examination of persons living in infected centers 

to determine the incidence of infection. 

3. Screening sleeping and living quarters; use of mosquito 

nets. 

4. Killing mosquitoes in living quarters. 

Measles 

1. Infectious agent. — A filterable virus. 

2. Source of infection. — Buccal and nasal secretions of an infected in- 

dividual. 

3. Mode of transmission. — Directly from person to person; indirectly 

through articles freshly soiled with the buccal and nasal discharges 
of an infected individual. The most easily transmitted of all com- 
municable diseases. 

4. Incubation period. — Seven to eighteen days; usually 14 days. 

5. Period of communicability. — During the period of catarrhal symptoms 

and until the cessation of abnormal mucous membrane secretions — 
minimum period of seven days from two days before to five days 
after the appearance of the rash. 

6. Methods of control: 

(A) The infected individual and his environment — 

1. Becognition of the disease — Clinical symptoms. Special 

attention to rise of temperature, Koplik spots and ca- 
tarrhal symptoms in exposed individuals. 

2. Isolation — During period of communicability. 

3. Immunization — None. 

4. Quarantine — Exclusion of exposed susceptible school 

children and teachers from school until 14 days from 
last exposure. This applies to exposure in the house- 
hold. Exclusion of exposed susceptible children from 
all public gatherings for the same period. 

5. Concurrent! disinfection — All articles soiled with the se- 

cretions of the nose and throat. 
C. Terminal disinfection — Thorough cleaning. 



THE CONTROL OF COMMUNICABLE DISEASES 359 

(B) General measures — 

1. Daily examination of exposed children and of other pos- 

sibly exposed persons. This examination should include 
record of the body temperature. A nonimmune exposed 
individual exhibiting a rise of temperature of 0.5 °C. or 
more should be promptly isolated pending diagnosis. 

2. Schools should not be closed or classes discontinued where 

daily observation of the children by a physician or 
nurse is provided for. 

3. Education as to special danger of exposing young children 

to those exhibiting acute catarrhal symptoms of any 
kind. 

Mumps 

1. Infective organism. — Unknown. 

2. Source of infection. — Secretions of the mouth and possibly of the 

nose. 

3. Mode of transmission. — By direct contact with an infected person or 

with articles freshly soiled with the discharges from the nose or 
throat of such infected person. 
4.. Incubation period. — From 4 to 25 days. The most common period, 
18 days, accepted as usual. A period of 21 days is not uncommon. 

5. Period of communicatility. — Unknown, but assumed to persist until 

the parotid gland has returned to its normal size. 

6. Methods of control: 

(A) The infected individual and his environment — 

1. Eecognition of the disease — Inflammation of Steno's duct 

may be of assistance in recognizing the early stage of 
the disease. The diagnosis is usually made on swelling 
of the parotid gland. 

2. Isolation — Separation of the patient from nonimmune 

children and exclusion of the patient from school and 
public places for the period of presumed infectivity. 
(See 5). 

3. Immunization — None. 

4. Quarantine — Limited to exclusion of nonimmune children 

from school and public gatherings for 21 days after 
last exposure to a recognized case. 

5. Concurrent disinfection — All articles soiled with the dis- 

charges from the nose and throat of the patient. 

6. Terminal disinfection — None. 
B) General measures — 

None, 



360 HYGIENE: DENTAL AND GENERAL 

Paratyphoid Fever 

1. Infectious agent: Bacillus paratyphosus A or B. 

2. Source of infection: Bowel discharges and urine of infected persons, 

and foods contaminated with such discharges of infected persons 
or of healthy carriers. Healthy carriers may be numerous in an 
outbreak. 

3. Mode of transmission: Directly by personal contact; indirectly by 

contact with articles freshly soiled with the discharges of infected 
persons or through milk, water, or food contaminated by such dis- 
charges. 

4. Incubation period: Four to ten days; average, seven days. 

5. Period of communioability : From the appearance of prodromal symp- 

toms, throughout the illness and relapses, during convalescence, and 
until repeated bacteriological examination of discharges show ab- 
sence of the infecting organism. 

6. Methods of Control: 

(A) The infected individual and his environment — 

1. Eecognition of the disease — Clinical symptoms, confirmed 

by specific agglutination test, and by bacteriological ex- 
amination of blood, bowel discharges or urine. 

2. Isolation — In fly-proof room, preferably under hospital 

conditions, of such cases as can not command adequate 
sanitary environment and nursing care in their homes. 

3. Immunization of exposed susceptibles. 

4. Quarantine — None. 

5. Concurrent disinfection — Disinfection of all bowel and 

urinary discharges and articles soiled with them. 

6. Terminal disinfection — Cleaning. 

(B) General measures — 

1. Purification of public water supplies. 

2. Pasteurization of public milk supplies. 

3. Supervision of other food supplies and of food handlers.* 

4. Prevention of fly breeding. 

5. Sanitary disposal of human excreta. 

6. Extension of immunization by vaccination as far as prac- 

ticable. 

7. Supervision of paratyphoid carriers and their exclusion 

from the handling of foods. 

8. Systematic examination of fecal specimens, from those 

who have been in contact with recognized cases, to detect 
carriers. 



*The human disease paratyphoid fever should not be confused with cases of food 
poisoning, or infection due to enteritidis bacilli of animal origin. 



THE CONTROL OF COMMUNICABLE DISEASES 361 

9. Exclusion of suspected milk supplies pending discovery of 
the person or other cause of contamination of the milk. 
10. Exclusion of water supply, if contaminated, until ade- 
quately treated with hypochlorite or other efficient dis- 
infectant, or unless all water used for toilet, cooking, 
and drinking purposes is boiled before use. 

Plague 

(Bubonic, Septicemic, Pneumonic) 

1. Infectious agent. — Bacillus pestis. 

2. Source of infection. — Blood of infected persons and animals, and 

sputum of human cases of plague pneumonia. 

3. Mode of transmission. — Direct, in the pneumonic form. In other 

forms the disease is generally transmitted by the bites of fleas 
(Loemopsylla cheopis and Ceratophyllus fasciatus), by which the 
disease is carried from rats to man, also by fleas from other rodents. 
Accidental, by inoculation, or by the bites of infected animals. 
Bedbugs may transmit the infection; flies may possibly convey the 
infection. 

4. Incubation period. — Commonly from 3 to 7 days, although occasionally 

prolonged to 8 or even 14 days. 

5. Period of communicability. — Until convalescence is well established, 

period undetermined. 

6. Methods of control: 

(A) The infected individual and his environment — 

1. Recognition of the disease — Clinical symptoms, confirmed 

by bacteriological examination of blood, pus from 
glandular lesions, or sputum. 

2. Isolation — Patient in hospital if practicable ; if not, in 

a screened room which is free from vermin." 

3. Immnuization — Passive immunization of known exposed 

contacts; active immunization of those who may be ex- 
posed. 

4. Quarantine — Contacts for seven days. 

5. Concurrent disinfection — All discharges and articles 

freshly soiled therewith. 

6. Terminal disinfection — Thorough cleaning followed by 

thorough disinfection. 



*In plague pneumonia, personal prophylaxis, to avoid droplet infection, must b( 
carried out by persons who come in contact with the sick. Masks or veils of I I 
cloth should be worn as protective measures. 



362 HYGIENE: DENTAL AND GENERAL 

(B) General measures — 

1. Extermination of rats and vermin by use of known 

methods for their destruction; destruction of rats on 
ships arriving from infected ports; examination of 
rats, ground squirrels,, etc., in areas where the infec- 
tion persists, for evidence of endemic or epidemic prev- 
alence of the disease among them. 

2. Supervision of autopsies of all deaths during epidemics. 

3. Supervision of the disposal of the dead during epidemics, 

whether by burial, transfer, or holding in vault, what- 
ever the cause of death. 

4. Cremation, or burial in quick lime, of those dying of this 

disease. 

Poliomyelitis 

1. Infectious agent: Not definitely determined. Believed to be a filter- 

able virus. 

2. Source of infection: Nose, throat, and bowel discharges of infected 

persons or articles recently soiled therewith. Healthy carriers are 
supposed to be common. 

3. Mode of transmission: By direct contact with an infected person or 

with a carrier of the virus, or indirectly by contact with articles 
freshly soiled with the nose, throat, or bowel discharges of such 
persons. 

4. Incubation period: From 3 to 10 days, commonly 6 days. 

5. Period of communicability : Unknown; apparently not more than 21 

days from the onset of disease, but may precede onset of clinical 
symptoms by several days. 

6. Metlwds of control: 

(A) The infected individual and his environment — 

1. Becognition of the disease — Clinical symptoms, assisted 

by chemical and microscopical examination of the spinal 
fluid. 

2. Isolation of all recognized cases in screened rooms. 

3. Immunization — None. 

4. Quarantine of exposed children of the household and of 

adults of the household whose vocation brings them into 
contact with children, or who are food handlers, for 14 
days from last exposure to a recognized case. 

5. Concurrent disinfection — Nose, throat, and bowel dis- 

charges and articles soiled therewith. 

6. Terminal disinfection — Cleaning. 



THE CONTROL OF COMMUNICABLE DISEASES 363 

(B) General measures during epidemics — 

1. Search for and examination of all sick children should be 

made. 

2. All children with fever should be isolated pending diag- 

nosis. 

3. Education in such technique of bedside nursing as will 

prevent the distribution of infectious discharges to 
others from cases isolated at home. 

Rabies 

1. Infectious agent: Unknown. 

2. Source of infection: Saliva of infected animals, chiefly dogs. 

3. Mode of transmission: Inoculation with saliva of infected animals 

through abrasion of skin or mucous membrane, almost always by 
bites or scratches. 
4. Incubation period: Usually 2 to 6 weeks. May be prolonged to 6 
months or even longer. 

5. Period of communicability : For 15 days in the dog (not known in 

man) before the onset of clinical symptoms and throughout the 
clinical course of the disease. 

6. Methods of control: 

(A) The infected individual and his environment — 

1. Eecognition of the disease — Clinical symptoms, confirmed 

by the presence of Negri bodies in the brain of an in- 
fected animal, or by animal inoculations with material 
from the brain of such infected animal. 

2. Isolation — None if patient is under adequate medical su- 

pervision, and the immediate attendants are warned of 
possibility of inoculation by human virus. 

3. Immunization — Preventive vaccination (Pasteur treat- 

ment) after exposure to infection by inoculation. 

4. Quarantine — None. 

5. Concurrent disinfection of saliva of patient and articles 

soiled therewith. 

6. Terminal disinfection — Thorough cleaning. 

(B) General measures — 

1. Muzzling of dogs when on public streets, or in places to 

which the public has access. 

2. Detention and examination of dogs suspected of having 

rabies. 

3. Immediate antirabic treatment of people bitten by dogs 

or by other animals suspected or known to have rabies, 
unless the animal is proved not to be rabid by subse- 
quent observation or by microscopic examination of the 
brain and cord. 



364 HYGIENE: DENTAL AND GENERAL 

Pneumonia 

(Acute Lobar) 

1. Infectious agent. — Various pathogenic bacteria commonly found in 

the nose, throat, and mouth, such as the pneumococcus, the baccillus 
of Friedlander, the influenza bacillus, etc. 

2. Source of infection. — Discharges from the mouth and nose of appar- 

ently healthy carriers, as well as of recognized infected individuals, 
and articles freshly soiled with such discharges. 

3. Mode of transmission. — By direct contact with an infected person, or 

with articles freshly soiled with the discharges from the nose or 
throat of, and possibly from infected dust of rooms occupied by, 
infected persons. 

4. Incubation period. — Short, usually two to three days. 

5. Period of communicability . — Unknown; presumably until the mouth 

and nasal discharges no longer carry the infectious agent in an 
abundant amount or in a virulent form. 

6. Methods of control: 

(A) The infected individual and his environment — 

1. Eecognition of the disease — Clinical symptoms. Specific 

infecting organisms may be determined by serological 
and bacteriological tests early in the course of the dis- 
ease. 

2. Isolation — Patient during clinical course of the disease. 

3. Immunization — None; vaccines are worthy of further 

careful trial. 

4. Quarantine — None. 

5. Concurrent disinfection — Discharges from the nose and 

throat of the patient. 

6. Terminal disinfection — Thorough cleaning, airing, and 

sunning. 

(B) General measures — 

In institutions and camps, when practicable, people in large 
numbers should not be congregated closely within doors. 
The general resistance should be considered by good 
feeding, fresh air, temperance in the use of alcoholic 
beverages, and other hygienic measures. 

Note. — The early reporting of pneumonia is highly desirable in view of its com- 
municability and the possibility of effective treatment of certain types with cura- 
tive sera. 

Rocky Mountain Spotted or Tick Fever 

1. Infectious agent. — Unknown. 

2. Source of infection. — Blood of infected animals, and infected ticks 

(Dermacentor species). 



THE CONTROL OF COMMUNICABLE DISEASES 365 

3. Mode of transmission. — By bites of infected ticks. 

4. Incubation period. — Three to ten days, usually seven days. 

5. Period of communicability . — Has not been definitely determined, prob- 

ably during the febrile stage of the disease. 

0. Methods of control : 

(A) The infected individual and his environment — 

1. Recognition of the disease — By clinical symptoms of the 

disease in areas where the disease is known to be en- 
demic. 

2. Isolation — None, other than care exercised to protect pa- 

tients from tick bites when in endemic areas. 

3. Immunization — None. 

4. Quarantine — None. 

5. Concurrent disinfection — None. All ticks on the patient 

should be destroyed. 

6. Terminal disinfection — None. 

(B) General measures — 

1. Personal prophylaxis of persons entering the infected 

zones during the season of ticks, by wearing tick-proof 
clothing, and careful daily search of the body for ticks 
which may have attached themselves. 

2. The destruction of ticks by clearing and burning vegeta- 

tion on the land in infected zones. 

3. The destruction of ticks on domestic animals by dipping, 

and the pasturing of sheep on tick infested areas where 
the disease is prevalent, with the object of diminishing 
the number of ticks. 

4. The destruction of small mammalian hosts as ground 

squirrels, chipmunks, etc. 

Scarlet Fever 

1. Infectious agent. — Unknown. 

2. Source of infection. — The belief at present is that the virus is con- 

tained in the secretions from the nose and throat, in the blood and 
in the lymph nodes, and that it is given off in the discharges from 
the mouth, the nose, the ears, and from brokendown glands of in- 
fected persons. 

3. Mode of transmission. — Directly by personal contact with an infected 

person; indirectly by articles freshly soiled witli discharges of an 
infected person, or through contaminated milk. 

4. Incubation period. — Two to seven days, usually three or four days. 

5. Period of communicability. — Four weeks from the onset of the disease, 

without regard to desquamation, and until all abnormal discharges 
have stopped and all open sores have healed. 



366 HYGIENE: DENTAL AND GENERAL 

6. Methods of control. — 

(A) The infected individual and his environment — 

1. Eecognition of the disease — By clinical symptoms. 

2. Isolation — In home or hospital, maintained in each case 

until the end of the period of infectivity. 

3. Immunization — None. 

4. Quarantine — Exclusion of exposed susceptible children 

and teachers from school, and food handlers from their 
work, until seven days have elapsed since last exposure 
to a recognized case. 

5. Concurrent disinfection — Of all articles which have been 

in contact with a patient and all articles soiled with 
discharges of the patient. 

6. Terminal disinfection — Thorough cleaning. 

(B) General measures — 

1. Daily examination of exposed children and of other pos- 

sibly exposed persons for a week after last exposure. 

2. Schools should not be closed where daily observation of 

the children by a physician or nurse can be provided for. 

3. Education as to special danger of exposing young children 

to those exhibiting acute catarrhal symptoms of any 
kind. 

4. Pasteurization of milk supply. 

Septic Sore Throat 

1. Infectious agent. — Streptococcus (hemolytic type). 

2. Source of infection. — The human naso-pharynx, usually the tonsils, 

any case of acute streptococcus inflammation of these structures be- 
ing a potential source of infection, including the period of convales- 
cence of such cases. The udder of a cow infected by the milker is 
an occasional source of infection. In such udders the physical signs 
of mastitis are usually absent.* 

3. Mode of transmission. — Direct or indirect human contact; consump- 

tion of raw milk from an infected udder. 

4. Incubation period. — One to three days. 

5. Period of commumcdbility . — In man, presumably during the continu- 

ance of clinical symptoms; in the cow, during the continuance of 
discharge of the streptococci in the milk, the condition in the udder 
tending to a spontaneous subsidence. The carrier stage may follow 
convalescence and persist for some time. 



*Mastitis in the cow, due to bovine streptococci, is not a cause of septic sore 
throat in humans unless a secondary infection of the udder by a human type of 
streptococcus takes place. 



THE CONTROL OF COMMUNICABLE DISEASES 367 

6. Methods of control: 

(A) The infected individual and his environment — 

1. Recognition of the disease — Clinical symptoms. Bac- 

teriological examination of the lesions or discharges from 
the tonsils and naso-pharynx may be useful. 
2. Isolation — During the clinical course of the disease and 
convalescence, and particularly exclusion of the patient 
from participation in the production or handling of milk 
or milk products. 

3. Immunization — None. 

4. Quarantine — None. 

5. Concurrent disinfection — Articles soiled with discharges 

from the nose and throat of the patient. 

6. Terminal disinfection — Cleaning. 

(B) General measures — 

.1. Exclusion of suspected milk supply from public sale or 
use, until pasteurized. The exclusion of the milk of 
an infected cow or cows in small herds is possible when 
based on bacteriological examination of the milk of 
each cow, and preferably the milk from each quarter of 
the udder at frequent intervals. 

2. Pasteurization of all milk. 

3. Education in the principles of personal hygiene and avoid- 

ance of the use of common towel, drinking and eating 
utensils. 

Smallpox 

1. Infectious agent. — Unknown. 

2. Source of infection. — Lesions of the skin and mucous membranes of 

infected persons. 

3. Mode of transmission. — By direct personal contact; by articles soiled 

with discharges from lesions. The virus may be present in all body 
discharges, including feces and urine. It may be carried by flies. 

4. Incubation period. — Twelve to fourteen days. (Cases with incubation 

period of 21 days are reported.) 

5. Period of communicability. — From first symptoms to disappearance 

of all scabs and crusts. 
6 Methods of control: 

(A) The infected individual and his environment — 

1. Eecognition of the disease — Clinical symptoms. Tests for 

immunity may prove useful. 

2. Isolation — Hospital' isolation in screened wards, free from 

vermin, until the period of infectivity is over. 



368 HYGIENE: DENTAL AND GENERAL 

3. Immunization — Vaccination. 

4. Quarantine — Segregation of all exposed persons for 21 

days from date of last exposure, or until protected by 
vaccination. 

5. Concurrent disinfection of all discharges and articles 

soiled therewith. 

6. Terminal disinfection — Thorough cleaning and disinfec- 

tion of premises. 
(B) General measures — 

General vaccination in infancy, revaccination of children on 
entering school, and of entire population when the dis- 
ease is prevalent. 

Note. — Adjustment of the time of vaccination of infants to avoid teething or 
other mild and common indispositions, the time of vaccination of children of the 
runabout age and older with preference for the cool months of the year, and the 
manner of vaccination with preference for the single puncture or small area scratch 
method through the droplet of virus are important to observe in order to avoid 
possible complications or secondary and subsequent infections at the site of vac- 
cination. Vaccination before the age of six months is particularly desirable. 

Syphilis 

1. Infectious agent. — Treponema pallidum. 

2. Source of infection. — Discharges from the lesions of the skin and 

mucous membranes, and the blood of infected persons, and articles 
freshly soiled with such discharges or blood in which the Treponema 
pallidum is present. 

3. Mode of transmission. — By direct personal contact with infected 

persons, and indirectly by contact with discharges from lesions or 
with the blood of such persons. 

4. Incubation period. — About three weeks. (In rare instances reported 

to have been as long as 70 days.) 

5. Period of communicability. — As long as the lesions are open upon the 

skin or mucous membranes and until the body is freed from the 
infecting organisms, as shown by microscopic examination of mate- 
rial from ulcers and by serum reactions. 

6. Methods of control: 

(A) The infected individual and his environment — 

1. Eecognition of the disease — Clinical symptoms, confirmed 

by microscopical examination of discharges, and by 
serum reactions. 

2. Isolation — Exclusion from sexual contact and from 

preparation or serving of food during the early and 
active period of the disease; otherwise none, unless the 
patient is unwilling to heed, or is incapable of observing, 
the precautions required by the medical adviser. 



THE CONTROL OF COMMUNICABLE DISEASES 369 

3. Immunization — None. 

4. Quarantine — None. 

5. Concurrent disinfection of discharges and of articles 

soiled therewith. 

6. Terminal disinfection — None. 
(B) General measures — 

1. Education in matters of sexual hygiene, particularly as 

to the fact that continence in both sexes and at all 
ages is compatible with health and development. 

2. Provision for accurate and early diagnosis and treatment, 

in hospitals and dispensaries, of infected persons, with 
consideration for privacy of record, and provision for 
following cases until cured. 

3. Repression of prostitution by use of the police power and 

control of use of living premises. 

4. Restriction of sale of alcoholic beverages. 

5. Restriction of advertising of services or medicines for 

treatment of sex diseases, etc. 

6. Abandonment of the use of common towels, cups, and 

toilet articles and eating utensils. 

7. Exclusion of persons in the communicable stage of the 

disease from participation in the preparing and serv- 
ing of food. 

8. Personal prophylaxis should be advised to those who ex- 

pose themselves to opportunity to infection. 

Tetanus 

1. Infectious agent: Bacillus tetani. 

2. Source of infection: Animal manure, and soil fertilized with animal 

manure, and, rarely, the discharges from wounds. 

3. Mode of transmission: Inoculation, or wound infection. 

4. Incubation period: Six to fourteen days, usually nine. 

5. Period of communicability : Patient not infectious except in rare in- 

stances where wound discharges are infectious. 

6. Methods of control: 

(A) The infected individual and his environment — 

1. Recognition of the disease — Clinical symptoms; may be 

confirmed bacteriologically. 

2. Isolation — None. 

3. Immunization — By antitoxin, single or repeated injection. 

4. Quarantine — None. 

;j. Concurrent disinfection — None. 
6. Terminal disinfection — None. 



370 HYGIENE: DENTAL AND GENERAL 

(B) General measures — 

1. Supervision of the practice of obstetrics. 

2. Educational propaganda such as ' l safety-first ' ' cam- 

paign, and ' ' safe and sane Fourth of July ' ; campaign. 

3. Prophylactic use of tetanus antitoxin "where wounds have 

been acquired in regions where the soil is known to be 
heavily contaminated, and in all cases where wounds 
are ragged or penetrating. 

4. Bemoval of all foreign matter as early as possible from 

all wounds. 

5. Supervision of biological products, especially vaccines 

and sera. 

Trachoma 

1. Infectious agent:* The chief, although not yet known to be the only, 

infectious agents are the hemoglobinophilic bacilli including the so- 
called Koch-Weeks bacillus. 

2. Source of infection: Secretions and purulent discharges from the con- 

junctivae and adnexed mucous membranes of the infected persons. 

3. Mode of transmission: By direct contact with infected persons and in- 

directly by contact with articles freshly soiled with the infective dis- 
charges of such persons. 

4. Incubation period: Undetermined. 

5. Period of comrrmmcability : During the persistence of lesions of the 

conjunctivae and of the adnexed mucous membranes or of discharges 
from such lesions. 

6. Methods of control: 

(A) The infected individual and his environment — 

1. Becognition of the disease — Clinical symptoms. Bac- 

teriological examination of the conjunctival secretions 
and lesions may be useful. 

2. Isolation. — Exclusion of the patient from general school 

classes. 

3. Immunization — None. 

4. Quarantine — None. 

5. Concurrent disinfection of discharges and articles soiled 

therewith. 

6. Terminal disinfection — None. 

(B) General measures — 

1. Search for cases by examination of school children, of 
immigrants, and among the families and associates of 
recognized cases; in addition, search for acute secret- 
ing disease of conjunctivae and adnexed mucous mem- 



It has not yet been proven that trachoma is due to one specific organism. 



THE CONTROL OF COMMUNICABLE DISEASES 371 

branes, both among- school children and in their fam- 
ilies, and treatment of such cases until cured. 

2. Elimination of common towels and toilet articles from 

public places. 

3. Education in the principles of personal cleanliness and 

the necessity of avoiding direct or indirect transfer- 
ence of body discharges. 

4. Control of public dispensaries where communicable eye 

diseases are treated. 

Trichinosis 

1. Infectious agent. — Trichinella spiralis. 

2. Source of infection. — Uncooked or insufficiently cooked meat of in- 

fected hogs. 

3. Mode of transmission. — Consumption of undercooked infected pork 

products. 

4. Incuoation period. — Variable; usually about one week. 

5. Period of communicability . — Disease is not transmitted by human 

host. 

6. Methods of control: 

(A) The infected individual and his environment — 

1. Recognition of the disease — Clinical symptoms, confirmed 

by microscopical examination of muscle tissue contain- 
ing trichinae. 

2. Isolation — None. 

3. Immunization — None. 

4. Quarantine — None. 

5. Concurrent disinfection — Sanitary disposal of the feces 

of the patient. 

6. Terminal disinfection — None. 

(B) General measures — 

1. Inspection of pork products for the detection of trichi- 

nosis. 

2. Thorough cooking of all pork products at a temperature 

of 160 °F. or over. 

Tuberculosis (Pulmonary) 

1. Infectious agent. — Bacillus tuberculosis (human). (In rare in- 

stances the bovine tubercle bacillus has been proved to be the 
cause of a pulmonary tuberculosis.) 

2. Source of infection. — The specific organism present in the discharges, 

or articles freshly soiled with the discharges from any open tubercu- 



372 HYGIENE: DENTAL AND GENERAL 

lous lesions/ the most important discharge being sputum. Of less 
importance are discharges from the intestinal and genito -urinary 
tracts, or from lesions of the lymphatic glands, bone, and skin. 

3. Mode of transmission. — Direct or indirect contact with an infected 

person by coughing, sneezing, or other droplet infection, kissing, 
common use of unsterilized food utensils, pipes, toys, drinking 
cups, etc., and possibly by contaminated flies and dust. 

4. Incubation period. — Variable and dependent upon the type of the 

disease. 

5. Period of communicability. — Exists as long as the specific organism 

is eliminated by the host. Commences when a lesion becomes an 
open one, i. e., discharging tubercle bacilli, and continues until 
it heals or death occurs. 

6. Methods of control: 

(A The infected individual and his environment — 

1. Recognition of the disease — By clinical symptoms and by 

thorough physical examination, confirmed by bacterio- 
logical examination and by serological tests. 

2. Isolation of such "open" cases as do not observe the 

precautions necessary to prevent the spread of the dis- 
ease. 

3. Immunization — None. 

4. Quarantine — None. 

5. Concurrent disinfection of sputum and articles soiled with 

it. Particular attention should be paid to prompt dis- 
posal or disinfection of sputum itself, of handkerchiefs, 
cloths, or paper soiled therewith, and of eating utensils 
used by the patient. 

6. Terminal disinfection — Cleaning and renovation. 
(B) General measures — 

1. Education of the public in regard to the dangers of 

tuberculosis and the methods of control, -with especial 
stress upon the danger of exposure and infection in early 
childhood. 

2. Provision of dispensaries and visiting-nurse service for 

discovery of early cases arid supervision of home cases. 

3. Provision of hospitals for isolation of advanced cases, and 

sanatoria for the treatment of early cases. 

4. Provision of open-air schools and preventoria for pre- 

tuberculous children. 

5. Improvement of housing conditions, and the nutrition of 

the poor. 

6. Ventilation, and elimination of dusts in industrial estab- 

lishments and places of public assembly. 



THE CONTROL OF COMMUNICABLE DISEASES 373 

7. Improvement of habits of personal hygiene and better- 

ment of general living conditions. 

8. Separation of babies from tuberculous mothers at birth. 

Tuberculosis (Other than Pulmonary) 

1. Infectious agent. — Bacillus tuberculosis (human and bovine). 

2. Source of infection. — Discharges from mouth, nose, bowels and genito- 

urinary tract of infected humans; articles freshly soiled with such 
discharges; milk from tuberculous cattle; rarely the discharging 
lesion of bones, joints, and lymph nodes. 

3. Mode of transmission. — By direct contact with infected persons, by 

contaminated food, and possibly by contact with articles freshly 
soiled with the discharges of infected persons. 

4. Incubation period. — Unknown. 

5. Period of communicauility. — Until lesions are healed. 

6. Methods of control: 

(A) The infected individual and his environment — 

1. Recognition of the disease — Clinical symptoms confirmed 

by bacteriological and serological examinations. 

2. Isolation. — None. 

3. Immunization. — None. 

4. Quarantine. — None. 

5. Concurrent disinfection. — Discharges and articles freshly 

soiled with them. 

6. Terminal disinfection. — Cleaning. 

(B) General measures — 

1. Pasteurization of milk and inspection of meats. 

2. Eradication of tuberculous cows from milch herds used 

in supplying raw milk. 

3. Patients with open lesions should be prohibited from 

handling foods which are consumed raw. 

Typhoid Fever 

1. Infection* agent. — Bacillus typhosus. 

2. Source of infection. — Bowel discharges and urine of infected individ- 

uals. Healthy carriers are common. 

3. Mode of transmission. — Conveyance of the specific organism by direct 

or indirect contact with a source of infection. Among indirect 
means of transmission are contaminated water, milk, and shellfish. 
Contaminated Hies have been common means of transmission in 
epidemics. 

4. Incubation period. — From 7 to 23 day-, averaging 10 to 14 days. 



374 HYGIENE: DENTAL AND GENERAL 

5. Period of communicability. — From the appearance of prodromal 

symptoms, throughout the illness and relapses during convalescence, 
and until repeated bacteriological examinations of the discharges 
show persistent absence of the infecting organism. 

6. Methods of control : 

(A) The infected individual and his environment — 

1. Eecognition of the disease — Clinical symptoms, confirmed 

by specific agglutination test and bacteriological exami- 
nation of blood, bowel discharges, or urine. 

2. Isolation — In fly-proof room, preferably under hospital 

conditions, of such cases as can not command adequate 
sanitary environment and nursing care in their homes. 

3. Immunization — Of susceptibles who are known to have 

been exposed or are suspected of having been exposed. 

4. Quarantine — None. 

5. Concurrent disinfection — Disinfection of all bowel and 

urinary discharges and articles soiled with them. 

6. Terminal disinfection — Cleaning. 

(B) General measures — 

1. Purification of public water supplies. 

2. Pasteurization of public milk supplies. 

3. Supervision of other food supplies, and of food handlers. 

4. Prevention of fly breeding. 

5. Sanitary disposal of human excreta. 

6. Extension of immunization by vaccination as far as prac- 

ticable. 

7. Supervision of typhoid carriers and their exclusion from 

the handling of foods. 

8. Systematic examination of fecal specimens from those 

who have been in contact with recognized cases, to de- 
tect carriers. 

9. Exclusion of suspected milk supplies pending discovery 

of the person or other cause of contamination of the 
milk. 
10. Exclusion of water supply, if contaminated, until ade- 
quately treated with hypochlorite or other efficient dis- 
infectant, or unless all water used for toilet, cooking, 
and drinking purposes is boiled before use. 

Typhus Fever 

1. Infectious agent: Bacillus typhi-exanthematici is claimed to be the 

causative agent; not yet definitely determined. 

2. Source of infection: The blood of infected individuals. 



THE CONTROL OF COMMUNICABLE DISEASES 375 

3. Mode of transmission: Infectious agent transmitted by lice. (Pedic- 

ulus corporis, P. capitis.) 

4. Incubation period: Five to twenty days, usually twelve days. 

5. Period of communicability: Until 36 hours have elapsed after the 

temperature reaches normal. 

6. Methods of control: 

(A) The infected individual and his environment — 

1. Eecognition of the disease — Clinical symptoms. (Con- 

firmation by bacteriological examination of blood 
claimed by Plotz.) 

2. Isolation — In a vermin-free room. All attendants should 

wear vermin-proof clothing. 

3. Immunization — Claimed to be practicable by use of vac- 

cine (Plotz, Olitzky, and Baehr). Not yet generally 
accepted. 

4. Quarantine — Exposed susceptibles for 12 days after last 

exposure. 

5. Concurrent disinfection — None. 

6. Terminal disinfection — Destroy all vermin and vermin 

eggs on body of patient, if not already accomplished. 
Destroy all vermin and eggs on clothing. Eooms to be 
rendered free from vermin. 

(B) General measures — ■ 

Delousing of persons, clothing, and premises during epi- 
demics, or when they have come or have been brought 
into an uninfected place from an infected community. 

Whooping Cough 

1. Infectious agent: Bacillus pertussis (Bordet, Gengou). 

2. Source of infection: Discharges from the laryngeal and bronchial 

mucous membranes of infected persons (sometimes also of infected 
dogs and cats, which are known to be susceptible). 

3. Mode of transmission : Contact with an infected person or animal or 

with articles freshly soiled with the discharges of such person or 
animal. 

4. Incubation period: Within 14 days. 

5. Period of communicability: Particularly eojnmunicable in the early 

catarrhal stages before the characteristic whoop makes the clinical 
diagnosis possible. Communicability probably persists not longer 
than two weeks after the development of the characteristic Avhoop 
or approximately four weeks after the onset of catarrhal symptoms. 

6. Methods of control: 

(A) The infected individual and his environment — 



376 HYGIENE: DENTAL AND GENERAL 

1. Eecognition of the disease — Clinical symptoms, supported 

by a differential leucocyte count, and confirmed where 
possible by bacteriological examination of bronchial se- 
cretions. 

2. Isolation — Separation of the patient from susceptible 

children, and exclusion of the patient from school arid 
public places, for the period of presumed infectivity. 

3. Immunization — Use of prophylactic vaccination recom- 

mended by some observers. Not effective in all cases. 

4. Quarantine — Limited to the exclusion of nomimmune chil- 

dren from school and public gatherings for 14 days 
after their last exposure to a recognized case. 

5. Concurrent disinfection — Discharges from the nose and 

throat of the patient and articles soiled with such dis- 
charges. 

6. Terminal disinfection — Cleaning of the premises used by 

the patient. 
(B) General measures — 

Education in habits of personal cleanliness and in the dan- 
gers of association or contact with those showing ca- 
tarrhal symptoms with cough. 

Yellow Fever 

1. Infectious agent. — Unknown. 

2. Source of infection. — The blood of infected persons. 

3. Mode of transmission. — By the bite of infected Aedes calopus mos- 

quitoes. 

4. Incubation period. — Three to five days, occasionally six days. 

5. Period of communicaoility .—First three days of the fever. 

6. Methods of control: 

(A) The infected individual and his environment — 

1. Recognition of the disease — Clinical symptoms. 

2. Isolation — Isolate from mosquitoes in a special hospital 

ward or thoroughly screened room. If necessary the 
room or ward should be freed from mosquitoes by fumi- 
gation. Isolation necessary only for the first three 
days of the fever. 

3. Immunization — None. 

4. Quarantine — Contacts for six days. 

5. Concurrent disinfection — None. 

6. Terminal disinfection — None. Upon termination of case 

the premises should be rendered free from mosquitoes by 
fumigation. 



THE CONTROL OF COMMUNICABLE DISEASES 377 

(B) General measures — 

Eliminate mosquitoes by rendering breeding impossible. 

(C) Epidemic measures — 

1. Inspection service for the detection of those ill with the 

disease. 

2. Fumigation of houses in which cases of disease have 

occurred, and of all adjacent houses. 

3. Destruction of Aedes calopus mosquitoes by fumigation; 

use of larvicides; eradication of breeding places. 



APPENDIX B 

DISINFECTION AND DISINFECTANTS 

The purpose of adding this appendix is to give a brief state- 
ment of the chemical and physiological principles involved in 
the action of the various disinfectants and certain facts rel- 
ative to their use, which may be convenient for the reference 
of the dental practitioner. 

Definitions. — A few definitions will be necessary as a basis 
for discussion. 

Disinfection means the destruction of the agents causing 
infection. 

Sterilization refers to the destruction of all forms of life 
in a certain medium or location. 

Sepsis is a bacteriological process of decay. 

Antiseptics are substances which prevent decomposition 
and decay. They do not necessarily destroy the organisms. 

Asepsis is the absence of living organisms. 

A germicide is a substance which has the power of destroy- 
ing germs. 

A deodorant is a substance which destroys or neutralizes the 
odors arising from the putrefaction or fermentation of organic 
substances. 

Disinfection Versus Sterilization. — Most organisms which 
produce disease are not spore-forming and it is, therefore, 
possible to disinfect in most instances without complete steri- 
lization. Material containing the bacilli of tetanus and an- 
thrax or the bacillus of malignant edema or B. welchii re- 
quires sterilization because these bacilli form spores. 

Dry heat at a temperature of 160° C. or a temperature of 
150° C. maintained for one hour will kill spores. Steam 
under a pressure of 15 pounds per square inch will kill spores 

37S 



DISINFECTION AND DISINFECTANTS 379 

in fifteen minutes. Steam at 15 lbs. pressure has a tempera- 
ture of about 120° C. 

Antiseptics. — Sugar and salt are the ordinary household 
antiseptics. These substances like freezing or drying prevent 
the development of the microorganisms which may still remain 
alive. "Weak solutions of certain disinfectants like mercury 
bichloride are antiseptic substances. 

Deodorants. — Dryness is the great natural deodorant. Sub- 
stances which are thoroughly dried will not give off disagree- 
able smells. An example of this is seen in the sanitary dry 
privy. Dryness sufficient to deodorize, however, is not suf- 
ficent to sterilize or disinfect. 

Of the chemical substances formaldehyde is an excellent 
deodorant as well as germicide since it combines directly with 
the putrefactive substances to form new substances which are 
not malodorants. 

Fumigation. — Fumigation is a process of liberating gases 
or fumes for the purpose of destroying the causes of infection 
or possible carriers of infection. Fumigation may therefore 
be directed either against germs or against insects and other 
animals which spread disease. It is now chiefly used to kill 
insects and other animals. There is a wide difference be- 
tween fumigation and disinfection and the two words should 
not be used interchangeably. The ordinary fumigants are for- 
maldehyde gas, sulphur dioxide (S0 2 ), hydrocj^anic acid 
(HCN), the halogens, carbon bisulphide (CS 2 ), carbon 
tetrachloride (CC1 4 ), and pyrethrum. 

Disinfection. — It is important to know what to disinfect, 
how to disinfect, and when to disinfect in order that the work 
may be done efficiently and completely. Bedside and contin- 
uous disinfection is far more important than terminal fumiga- 
tion in preventing the spread of disease. In controlling any 
communicable disease the causative organism and modes of 
transmission should be thoroughly understood. 

Control of Disinfection. — The efficiency of a disinfecting 
process may be determined by saturating cotton threads with 



380 HYGIENE: DENTAL AND GENERAL 

a culture of B. prodigiosus, grown. in Dunham's Peptone 
Medium. These threads are subjected to the process of dis- 
infection with the other material, then planted in tubes of 
sterile broth where growth may be readily determined by the 
development of red color. 

Natural Disinfection. — Nature's disinfecting agencies in- 
clude (1) dilution, as exemplified by the purification of pol- 
luted water by storage, (2) sunlight, which kills organisms by 
its actinic rays; (3) dryness if sufficient and prolonged and 
(4) symbiosis, as exemplified in the destruction of disease 
germs in sewage by the action of the bacteria of putrefaction. 

The Ideal Disinfectant has not yet been found. Such a 
substance would be highly germicidal, free from organic mat- 
ter, reasonably stable, soluble or readily miscible in water 
forming a permanent emulsion ; it should be harmless to man 
and the higher animals, possessed of a good power of penetra- 
tion without bleaching fabrics or pigments and corroding 
metals. 

Standardizing Disinfectants. — In order that we may have 
a terminology by which the disinfecting power of a substance 
may be stated there has been developed a method of standard- 
izing disinfectants by comparing them with phenol. By this 
comparison the so-called carbolic coefficient is determined. 
This states the germicidal power of the given substance as 
compared with that of 5% carbolic acid. 

The test is limited to the effect of the germicide upon naked 
bacterial cells under favorable conditions for action. The 
time is constant and the strength of the disinfectant is varied. 
A 24-hour culture of B. typhosus, grown in bouillon after 
having been transplanted for three successive days, is used 
as a test organism. 

The steps in making the Ridedl-W alker test for standardiz- 
ing disinfectants are as follows: 

(1) Make up Standard solution of 5% phenol. 

(2) Prepare three test tubes using 5 c.c. of this in the fol- 



DISINFECTION AND DISINFECTANTS 381 

lowing dilutions : 1 to 90, 1 to 100, 1 to 110. Tubes 1 inch 
in diameter are used. 

(3) Various dilutions of the substance to be tested are 
made (5 c.c. being used in each test tube). 

(4) -All solutions as well as the cultures are brought to 20° 
C. on a water bath. 

(5) Add 0.1 c.c. of culture to each tube at intervals of 30 
sec. (Use tubes in groups of 5.) 

(6) At end of 2 J minutes begin to transplant with a stand- 
ard loop (4 mm. No. 14 wire U. S. Gauge) to broth culture. 
Transplant from each tube at the end of 2-J minute period. 

(7) Make a second transplanting from each tube when it 
has been exposed 5 minutes. 

(8) Incubate transplants 48 hours at 37° C. and read plus 
or minus. The carbolic coefficient is the factor obtained by 
dividing the highest dilution of the unknown disinfectant 
which permitted growth of both the 1\ and 5 minutes ex- 
posure by the highest dilution of the phenol which gave the 
same result. 

Physical Agents of Disinfection. — The following list enu- 
merates the physical means of disinfection with the briefest 
comment as to their use and efficiency. 

(1) Sunlight is an active germicide. It destroys spores as 
well as bacteria. The blue-violet and ultra-violet rays pos- 
sess germicidal power. 

(2) Vltra-Yiolet Rays kill spores and vegetative cells. 

(3) Electricity may kill germs either by thermal or electro- 
lytic action but it is not adapted to general or practical use. 

(4) Burning is best for those things which may be de- 
stroyed. 

(5) Dry heat, 150° C. for one hour will destroy both vege- 
tative cells and spores. Dry heat lacks penetration and is 
injurious to fabrics. 

(6) Boiling is very effective, and is particularly applicable 
to the disinfection of bedding, body linen, towels, fabrics of 
many kinds, kitchen and table ware, cuspidors, etc. The 



382 HYGIENE: DENTAL AND GENERAL 

efficacy of boiling water is increased by the addition of alco- 
hol, mercury bichloride or alkaline coal tar creosotes. Ten 
per cent sodium bicarbonate will prevent rusting. 

(7) Steam is satisfactory, reliable, quick and penetrating. 
It sterilizes, but shrinks woolens and injures silks. It ruins 
leather, furs, skins of all kinds, rubber shoes, oilcloth and 
articles containing rubber, glue, varnish or wood. 

GASEOUS DISINFECTION 

Terminal fumigation was formerly practiced following al- 
most every communicable disease but of late this practice has 
been largely discontinued. In most diseases the thorough air- 
ing and sunning of the room and the disinfection of all arti- 
cles which have come in contact with the patient are sufficient. 
There has been a false sense of security in fumigation and it 
has too frequently been carelessly carried out while the more 
important disinfection of contaminated material has been neg- 
lected. Many health departments continue to fumigate after 
smallpox, scarlet fever and diphtheria, but even this is likely 
to be abandoned. If it is done it should be certain that the 
room is made tight by pasting paper over cracks and holes 
and that the gases or fumes are liberated in proper quantity 
and given the proper time for action, under suitable conditions 
of temperature and moisture. Fumigation will always be con- 
tinued to kill animals which carry the germs of infectious 
disease. Whether rooms are fumigated or not they should 
always be renovated, cleaned and aired after a case of infec- 
tious disease. Continuous and terminal disinfection of con- 
taminated material should never be neglected. 

Formaldehyde Gas. — Formaldehyde is the most generally 
applicable gas for this type of disinfection. Neither this nor 
any other gas has great power of penetration and its use must 
be limited to surface disinfection. It is highly irritating but 
not poisonous to man and does not injure fabrics, colors, 
metals or paintings. Its specific gravity is about that of the 



DISINFECTION AND DISINFECTANTS 383 

air and it diffuses slowly. It is not an insecticide. It com- 
bines with decomposing nitrogenous substances and deodorizes 
them. It may kill spores and dry organisms. 

Formalin as it is purchased in the market is a 40 per cent 
solution of formaldehyde gas in water. At 20° C. the gas 
polymerizes and forms trioxymethylene, a white crystalline 
substance. 

There are two methods of liberating or driving off formal- 
dehyde gas by the heat liberated from chemical reactions. 

In the Permanganate-Formalin Method 25 grams of 
KMn0 4 are added to 500 c.c. of formalin for every 1000 cubic 
feet of air space. 

In the Formalin-Lime-Aluminum-Sulphate Method two solu- 
tions are used. Solution A contains 150 grams of aluminum 
sulphate dissolved in hot water (300 c.c). Solution B con- 
tains 600 c.c. of Formalin. Solutions one and two are mixed 
and poured upon 2000 grams of unslaked lime. These quan- 
tities give the proper amount of gas for 1000 cubic feet of air 
space. 

Exposure should be from six to twelve hours for disinfec- 
tion with the air at a temperature of 65° F. and at least 60 per 
cent saturated with moisture. 

Besides these methods of liberating formaldehyde gas there 
are other ways of disinfecting with it, viz. : (1) the autoclave 
under pressure, (2) the retort without pressure, (3) a gener- 
ator or lamp, (4) formaldehyde and dry heat in partial 
vacuum, (5) spraying formalin, (6) heating paraform. 

Sulphur Dioxide.— The gas S0 2 depends upon a combina- 
tion with water and the formation of sulphurous acid 
(H 2 S0 3 ) for its disinfecting action. Its efficiency, therefore, 
depends upon the moisture present in the air. It is heavier 
than air and readily soluble in water. It does not penetrate 
nor does it kill spores. 

The methods of fumigating with SO. include: (1) The 
Pot Method by which sulphur is burned in a metal dish, (2) 
The Liquid Sulphur Dioxide Method in which liquid S0 2 pur- 



384 HYGIENE: DENTAL AND GENERAL 

chased in tubes is allowed to evaporate, (3) The Sulphur 
Furnace method by which the fumes are poured into the room 
or space to be fumigated. 

Five pounds of sulphur per 1000 cubic feet of room space 
are required for germicidal action ; 2 lbs. per 1000 cubic feet 
of room space are required for insecticidal action. One pound 
of sulphur is the equivalent of 2 lbs. of liquid S0 2 . 

This gas is used primarily as an insecticide and in such 
capacity needs no moisture. When so used in a house mois- 
ture should be avoided as in the presence of water it rots 
fabrics, injures paintings and metallic fixtures, and bleaches 
pigment. The reaction time ranges from 6 to 12 hours. 

Oxyg"en in its nascent state is a good disinfectant. It kills 
by combining chemically with the albuminous matter of the 
bacterial cell. 

Hydrocyanic Acid is dangerous because it is so deadly a 
poison for man. It is a good insecticide but not a good ger- 
micide. It is not toxic to plants, but is particularly toxic to 
animals. It does not destroy paintings, furniture, draperies 
or carpets. It is slightly lighter than air, invisible, and has 
the odor of bitter almonds. 

It is evolved by the action of H 2 S0 4 on KCN: (1£ parts 
H 2 S0 4 , and 2y 4 parts H 2 0, to 1 part KCN). Mix the water 
and acid together then add potassium cyanide. Use 4 ounces 
to 5 ounces of KCN per 1000 cubic feet. Sometimes S0 2 is 
used with HCN because the odor of the sulphur will give 
warning of the more deadly gas. It is most used to rid iso- 
lated buildings and ships of vermin. 



LIQUID DISINFECTANTS 

Disinfecting solutions have great powers of penetration, 
whereas, emulsions do not penetrate but have a high ger- 
micidal action on a surface where the suspended material of 
the emulsion accumulates. 



DISINFECTION AND DISINFECTANTS 385 

Mercuric Chloride (HgCl 2 ) is a valuable germicide, de- 
structive to all microbial life in weak solutions. It kills both 
germs and spores but does not deodorize. It is highly poison- 
ous. It corrodes metals and forms insoluble and inert com- 
pounds with albuminous matter. 

HgCl 2 is a white, volatile and crystalline substance, dis- 
solving in 16 parts of cold water and 3 parts of boiling water. 
It is highly soluble in alcohol. HC1, NaCl, and NH 4 C1 aid 
in its solution. It is decomposed by lead, copper and other 
metals. It is used in dilutions of 1 :500 or 1 :1000. A solu- 
tion of 1 :1000 kills vegetative cells in y 2 hour. A 1 :500 
dilution kills spores in 1 hour. A 1 :1000 solution = 1 gm. 
per liter or 1 dram per gal. 

Formalin is a forty per cent solution of formaldehyde gas 
in water. It acts well in the presence of albuminous matter 
and is not injurious to most articles. It is a true deodorant 
and not very poisonous to man although it is unstable and 
polymerizes in cold weather to form trioxymethylene. Hot 
formalin attacks iron and steel but does not attack copper, 
brass, nickel, or zinc. It has no detrimental effect on fibers 
and does not bleach colors but it renders leather and furs 
brittle. A ten per cent solution of formaldehyde is equiv- 
alent to a 1 to 500 solution of HgCl 2 and superior to 5 per 
cent phenol. Feces are deodorized (and disinfected when 
thoroughly mixed) by 10 per cent formalin. 

Potassium Permanganate (KMnOJ has limited application 
since it is readily reduced by organic matter but it is a good 
germicide in surgical practice. It is a dark purple, crystalline 
substance and has a sweet astringent taste. Probably free 
nascent oxygon is the true disinfecting agent. It kills vegeta- 
tive organisms and spores. It is soluble in 16 parts cold water 
and 2 parts boiling water. 

Lime is one of the best and cheapest disinfectants we have. 
It is used as slaked lime or as chlorinated lime for destroying 
infection in organic matter. CaO is obtained by calcinating 
or heating native OaC0 3 (chalk, limestone, or marble). The 



386 HYGIENE: DENTAL AND GENERAL 

addition of water to calcinated lime produces slaked lime 
which may be used for germicidal purposes. Slaked lime 
[Ca (0H) 2 ] is a mixture of one pint of water for every 2 
lbs. of calcinated lime. Lime absorbs about one-half its 
weight of water. Freshly slaked lime should be used, else 
C0 2 is absorbed from the air, and the slaked lime becomes 
inert CaC0 3 . 

Whitewash is slaked lime diluted with ten parts of water 
and mixed with glue. It is valuable for destroying spore free 
bacteria that have lodged on the surfaces of rooms, barns, 
stables, etc. 

Milk of Lime is slaked lime diluted with about 4 times its 
volume of water to a thick creamy consistency. It is useful 
for the disinfection of excreta and privy vaults. Freshly 
slaked lime must be used in its preparation. If older than 
a few days it is probably worthless. 

Ten per cent Ca (OH) 2 solution kills vegetative germs in 
a few hours; a 3 per cent Ca (OH) 2 solution kills typhoid 
in one hour; a 20 per cent Ca (OH) 2 solution will sterilize 
feces in one hour. 



DISINFECTION IN DENTAL PRACTICE 

Hands. — All dirt should be removed and the tissues kept 
in a soft condition ; short nails are easier to keep clean. Scrub 
with soap and water using a brush, and rinse off with 70 per 
cent alcohol. Solutions of HgCl 2 are more or less injurious 
to the hands but are often used. A 2 per cent solution of 
phenol followed by the use of a deodorant to remove odor 
may be used. 

Materials. — Instruments should be boiled and wiped off 
with alcohol. Boiling water is used for broaches, and broach 
holders, burnishers, burs, clamps, chisels, drills, excavators, 
explorers, hand pliers, pluggers, reamers, elevators, scissors, 
scalers and spatulas. Mirrors may be washed in hot water 
and wiped in alcohol. The glass table or instrument rest 



DISINFECTION AXD DISINFECTANTS 387 

should be washed with alcohol after each use to prevent spots 
of blood or mucus from getting onto instruments. Chip 
blower tips should be passed through the flame before using. 
Cotton rolls, cottonoid napkins, gauze and cotton pellets should 
be kept in closed glass jars. The engine hand piece may be 
boiled in green soap solution and should always be wiped 
with alcohol before using. Cotton and gauze materials may 
be sterilized by dry heat and kept in sealed packages. 

With the development of a more widespread and popular 
knowledge of bacteria and communicable disease many people 
watch both the personal hygiene of the dentist and his care 
of the instruments more closely than he suspects. 

The Office should be kept well aired and free from dust. 
Articles handled or mouthed by patients who may have an 
infectious disease should be burned or disinfected. Furniture 
handled by them may be washed in 5 per cent phenol. Nap- 
kins should be boiled. Paper cups and paper cuspidors 
should be used and burned. 



BIBLIOGRAPHY 



The following list of publications is designed for a brief 
working bibliography and is arranged according to chapter 
topics. 

GENERAL 

Bergey, D. H. : Principles of Hygiene, Philadelphia, Pa., 6th Edition, 

W. B-. Saunders Co. 
Egbert, Seneca: Hygiene and Sanitation, Philadelphia, Pa., 1919, Lea 

& Febiger. 
Fisher, I., and Fisk, E. L. : How to Live, New York, 1915, Funk & 

Wagnalls Co. 
Gardner, Fletcher: Practical Sanitation, St. Louis, 1916, 2nd Edition, 

C. V. Mosby Co. 

Lee, Roger I.: Health and Disease, 1917, Little, Brown & Co., Boston. 
Pyle, W. L. : Pyle 's Manual of Personal Hygiene, Philadelphia, Pa., 

7th Edition, W. B. Saunders Co. 
Rosenau, M. J. : Preventive Medicine and Hygiene, New York, 1916, 

D. Appleton & Co. 

Stiles, P. G. : Human Physiology, Philadelphia, Pa., 1919, W. B. Saun- 
ders Co. 

Winslow, C.-E. A. : Handbook of Health in War and Peace, New York, 
1917, The Century Co. 

DENTAL HYGIENE 

Black: Operative Dentistry, Chicago, 1917, Medico-Dental Publishing 
Co. 

Black : Special Dental Pathology, Chicago, 1915, Medico-Dental Pub- 
lishing Co. 

Brackett, C. A. : Care of the Teeth, Cambridge, Mass., 1915, Harvard 
University Press. 

Endelman and Wagner: General and Dental Pathology, St. Louis, 
' 1920, C. V. Mosby Co. 

Head, Joseph: Mouth Hygiene, Philadelphia, Pa., 1920, W. B. Saun- 
ders Co. 

Hccker, Friedrich : Pyorrhea Alveolaris, St. Louis, 1913, C. V. Mosby 
Co. 

389 



390 HYGIENE: DENTAL AND GENERAL 

Hutchinson: Food and Dietetics, New York, William Wood & Co. 

Pickerill: Prevention of Dental Caries and Oral Sepsis, Philadelphia, 
Pa., S. S. White Co. 

Prinz: Dental Materia Medica and Therapeutics, St. Louis, 5th Edi- 
tion, 1917, C. V. Mosby Co. 

Todd, T. Wingate : Mammalian Dentition, St. Louis, 1918, C. V. Mosby 
Co. 

NUTRITION 

Cannon, Walter B. : Bodily Changes in Pain, Hunger, Fear and Rage, 

New York, 1915, D. Appleton & Co. 
Howell, W. H.: Textbook of Physiology, Philadelphia, Pa., 1914, W. 

B'. Saunders Co. 
Lusk: Fundamentals of Nutrition, New Haven, Conn., 1914, Yale Uni- 
versity Press. 
Lusk: Elements of the Science of Nutrition, Philadelphia, Pa., 1917, 

W. B. Saunders Co. 
McCollum: Newer Knowledge of Nutrition. 
Sherman: Chemistry of Foods and Nutrition, New York, 1911, Mac- 

Millan Co. 
Taylor: Digestion and Metabolism, Philadelphia, Pa., 1912, Lea & 
Febiger. 
Special pamphlets on Diet may be secured from the United States 
Health Service, from the Children's Bureau of the United States Depart- 
ment of Labor, and from many State Departments of Health. 

HYGIENE OF THE CENTRAL NERVOUS SYSTEM 

Courtney: The Conquest of the Nerves, New York, 1911, MacMillan 

Co. 
Lickley: The Nervous System, New York, 1912, Longmans, Green & 

Co. 
Loeb: Comparative Physiology of the Brain, The Science Series, New 

York, 1900, G. P. Putnam's Sons. 
Stiles, Percy G.: The Nervous System, Philadelphia, Pa., 1914, W. B. 

Saunders Co. 
Thomson: Brain and Personality, 1907, Dodd, Mead & Co. 

THE HYGIENE OF REPRODUCTION 
Castle, W. E.: Genetics and Eugenics, Cambridge, Mass., 1916, Har- 
vard University Press. 
Conklin, E. G. : Heredity and Environment, Princeton, N. J., 1915, 

Princeton University Press. 
Davenport: Heredity in Relation to Eugenics, New York, 1911, Henry 
Holt & Co. 



BIBLIOGRAPHY 391 

Exner, M. J.: Rational Sex Life for Man, 1917. 

Galton: Eugenics, Its Definition, Scope and Science, 1905. 

Galton: Hereditary Genius, 1869. 

Poponoe and Johnson: Applied Eugenics, New York, 1918, MacMillan 

Co. 
Stopes: Married Love, Eifield, London. 

THE NEW SCIENCE OF DISEASE PEEYEXTIOX 

Councilman : Disease and Its Causes, New York, 1913, Henry Holt &: 

Co. 
Hamilton, Lady Claud: Louis Pasteur — His Life and Labors, (by his 

son-in-law), translated from the French, Xew Y'ork, 1885, D. Ap- 

pleton & Co. 
Sedgwick: Principles of Sanitary Science in Public Health, Xew Y'ork, 

1914, MaeAlillan Co. 

IMMUNITY 

Hiss, P. H., Jr., and Zinsser, Hans: A Textbook of Bacteriology, New 

York, 1918, D. Appleton & Co. 
Zinsser, Hans: Infection and Resistance, Xew Y'ork, 1916. MacMillan 

Co. 

SPECIFIC DISEASES 

Rosenau, M. J. : Preventive Medicine and Hygiene, Xew York, 1916, 

D. Appleton & Co. 
Stokes: Today's World Problem in Disease Prevention, 1919, U. S. 

Public Health Service. 
U. S. Public Health Service Reports on Influenza. 
Special Articles on Influenza and Articles on Venereal Disease, The 

American Journal of Public Health, Boston. 

PUBLIC HEALTH ADMINISTRATION 

McXutt, J. Scott: Manual for Health Officers, 1915, John Wiley & 
Sons. 

Overton and Denno: The Health Officer, Xew York, 1919, W. B. Saun- 
ders Co. 

Whipple, G. C: Vital Statistics, 1919, John Wiley & Sons. 

WATER SUPPLY 

American Public Health Association, Standard Methods for Water Anal- 

. ysis, 1920. 
Prescott and Winslow: Elements of Water Bacteriology, Xew York, 
1913, John Wiley & Sous. 



392 HYGIENE: DENTAL AND GENERAL 

Turneaure and Russell: Public Water Supplies, New York, 1914, John 

"Wiley & Sons. 
Weston and Turner: The Digestion of a Sewage Filter Effluent by a 

Small Stream, Contributions from Sanitary Research Laboratory, 

Vol. X, Massachusetts Institute of Technology, Cambridge, Mass. 
Whipple, G. C. : Microscopy of Drinking Water, New York, 1914, John 

Wiley & Sons. 
Woodman and Norton : Air, Water and Food, 1914, John Wiley & Sons. 

FOOD CONTROL 

Parker, Horatio N. : Milk Supply, New York, 1917, McGraw-Hill Co. 

Rosenau, M. J.: The Milk Question, Boston, Mass., 1912, Houghton 
Mifflin Co. 

Savage, W. G.: Milk and the Public Health, New York, 1912, Mac- 
Millan Co. 

Stiles, Percy G. : • Nutritional Physiology, Philadelphia, Pa., 3rd Edi- 
tion, W. B. Saunders Co. 

Report of the Commission on Milk Standards, New York Milk Commit- 
tee, Public Health Reports, May 10, 1912. 

WASTE DISPOSAL 

Metcalf and Eddy: American Sewerage Practice, New York, 1916, Mc- 
Graw-Hill Co. 

Public Health Bulletin, No. 101 : The Treatment of Sewage from Sin- 
gle Houses and Small Communities, Dec, 1919, U. S. Public 
Health Service. 

Kinnicutt, Winslow and Pratt: Sewage Disposal, New York, 1910, 
John Wiley & Sons. 

See also special references at the end of Chapter XIII. 

SCHOOL HYGIENE 

Berkowitz, J. H. : Standardization of Medical Inspection Facilities, 

1919, Bulletin No. 2, United States Bureau of Education. 
Clark, Taliaferro: School Medical Inspection, Sept., 1919, Reprint 

No. 554, U. S. Public Health Report. 
Gulick and Ayres: Medical Inspection of Schools, New York Charities 

Publishing Committee. 
Health Work Bulletin No. 50, part 7: The Public School System of 

Memphis, Tenn., 1919: United States Bureau of Education. 
Hogarth, A. H. : Medical Inspection of Schools, New York and London, 

1909, Oxford University Press. 
Hyatt, T. P.: The Relationship of Dental Conditions to the Physical, 

Moral, and Mental Development of a Child, 1919, Dental Cosmos. 



BIBLIOGRAPHY 393 

Pennsylvania Department of Health, Engineering Division: Manual of 
School Sanitation, Aug., 1919. 

Smith, John H. : Co-operation in the Control of Communicable Diseases 
Among School Children, New York State Department of Health, 
1918. 

INDUSTRIAL HYGIENE 

Goldmark and Brandeis: Fatigue and Efficiency, New York, 1912, 
Charities Publishing Committee. 

Mock, Harry E. : Industrial Medicine and Surgery, 1919, Philadelphia, 
W. B. Saunders Co. 

Oliver, Thomas: Diseases of Occupation, New York, 1909, E. P. Dut- 
ton & Co. 

Price, G. M. : The Modern Factory, New York, 1914, John Wiley & 
Sons. 

Health of Munition Workers, Committee Reports, His Majesty's Sta- 
tionery Office, London, 1917 and 1918. 

Studies in Vocational Diseases, published by the United States Public 
Health Service. 

Special pamphlets are available from the United States Public Health 
Service, Washington, D. C, and from many of the State Depart- 
ments of Health. 

Thompson, W. G. : The Occupational Diseases, New York, D. Appleton 
& Co. 

VENTILATION, HEATING AND LIGHTING 
Carpenter, R. C. : Heating and Ventilating of Buildings, New York, 

1915, John Wiley & Sons. 
Henderson: Paper read before Fifteenth International Congress on 

Hygiene and Demography. 
Hill, Leonard: Journal of Physiology, London, 1910. 
Hoffman and Raber: Handbook for Heating and Ventilating Engi- 
neers, 1913. 
Pfluge : Zeitschrif t fur Hygiene and Inf ections-krankheiten, Leipsic, 

1905, p. 363. 
Winslow, C.-E. A., and others: Standards for Measuring the Exhaust 

Systems in Polishing Shops, Reprint No. 509, U. S. Public Health 

Reports, March 7, 1919. 
Report of the New York Ventilating Commission, New York, 1915. 
The Science of Ventilation and Open-Air Treatment, published by His 

Majesty's Stationery Office, London, 1919. 

DISINFECTANTS 
Rosenau, M. J.: Preventive Medicine and Hygiene, New York, 191(3, 
. D. Appleton & Co. 



IXDEX 



Abnormalities, inherited, 88 
Accident insurance, 306 

prevention, 310 
Acid poisoning, 321 
Actinomycosis, 343 
Action, hygiene of, 51 
Activated sludge, 250 
Activity, bodily, 54 
Acute infectious conjunctivitis. 

343 
Adenoids. 24 
Administration, local health, 205 

of health in industry, 307 

of school hygiene, 281 

state health, 202 
Adulteration of food, 209 
Aerobic purification of sewage, 246 
Agglutinins, 136 
Air, cooling of, 335 

quality of, 323 . 

testing, 327 

■washing and humidifying, 334 
Alcohol, 76 
Alveolar process, 28 
Amboceptor, 137 
Amebic dysentery, 351 
Anaerobic purification of sewage, 

251 
Anaphylaxis, 133 
Anchylostomiasis, 344 
Antitoxins, 135 

discovery of, 117 
Anthrax, 345 

immunity in, 115 
Antiseptics, 378, 379 
Aitificial ventilation, 332 
Asepsis, 378 
Assimilation, 48 

Authority for health administra- 
tion, 188 
Autointoxication, 49 



B 



Bacillary dysentery, 352 
Bacillus botulinus, 222 
Bacteriological purification of sew- 
age, 246 
Balanced diet, 39 
Bathing, 65 

Benzene poisoning, 321 
Beri-Beri, 38 
Bodily defects, 75 
Body wastes, elimination of, 49 
Botulism, 222 
Breathing, 64 
Broad St. well, 118 



Calorie requirement, 40 

Carbohydrates, 35 

Caries, 144 

Carriers, 130, 340 

Central nervous system, hygiene 

of, 68 
Cesspool, 251, 263 
Cerebrospinal meningitis, 347 
Chemical closet, 245, 262 
Chemical precipitation of sewage, 

245 
Chemical purification of sewage, 

244 
Chicken pox, 348 
Child labor, 305 

Child's ten commandments, 106 
Chlorination of water, 241 
Chlorine in water analysis, 234 
Cholera, 348 
Cleaning, 340 
Clothing, 66 
Cocoa, 77 
Coffee, 77 

Colds, cause of, 181 
Color blindness, 87 
< uin fort meter, '.'>'■'>" 
( lommon cold, 180 



395 



396 



INDEX 



Common law, 196 
Communicable diseases, 108, 165 

control of, 339 
Complement, 137 
Concentration, mental, 69 
Conjunctivitis, infectious, 343 
Conn, H. W., 121 
Constipation, 51 
Contact, 341 
Contact beds, 265 
Contact of teeth, 19 
Cooling air, 335 



D 

Dairy score card, 214 
Defects, bodily, 75 
Defective school children, 275 
Defective vision, 285 
Deformities, of face and jaw, 24 

of feet, 62 
Dental care of school children, 286 
Dental floss, 159 
Dental hygiene, 17 
Dental hygienist, 153 
Dental instruments, disinfection 

of, 386 
Dentin, structure of, 27 
Dentistry, industrial, 315 
Delousing, 341 
Deodorants, 378, 379 
Dengue, 350 
Deposits on teeth, 152 
Diet, 33 

and tooth decay, 147 

balanced, 39 

varied, 42 
Dietary diseases, 38 
Digestion, 42 
Diphtheria, 350 

and antitoxin, 117 
Disease reactions, 130 
Diseases, communicable, 108, 165, 
339 

dietary, 38 

industrial, 319 

inherited, 88 

prevention of, 108 
. prevention in industry, 318 

systemic, and septic teeth, 161 

theories of, 108 
Disinfectants, liquid, 384 

standardization of, 380 
Disinfectant, the ideal, 380 



Disinfection, 341, 379 

and disinfectants, 378 

control of, 379 

gaseous, 382 

in dental practice, 386 

natural, 380 

physical agents of, 381 
Disposal of garbage, 267 

of manure, 269 

of sewage, 243 
Dreams, 72 

Drugs and immunity, 128 
Dysentery (amebic), 351 
Dysentery (bacillary), 352 



Emotions and digestion, 42 

and the nervous system, 7-i 
Emotions, hygiene of, 45 
Enamel, structure of, 26 
Endotoxins, 132 
Epidemic of Broad St. well, 118 

typhoid from oysters, 121 
Environment and heredity, 91 
Eugenics (see heredity) 
Exercise, 54 

rhythm in, 58 

types of, 57 
Exposure to wet and cold, 127 



Factory inspection, 306 
Fatigue and immunity, 127 

in industry, 305 
Fats in diet, 36 
Favus, 109, 353 
Federal health agencies, 194 

public health functions, 188 
Feeble-mindedness, 93 
Feet, deformities of, 62 
Fermentation and disease, 109 
Figure, 59 

Filtration of water, 240 
Fly breeding, prevention of, 263 
Food, adulteration of, 209 

control, 209 

in industry, 311 

poisoning, 51 

prepared, 223 

sanitation, 213 



INDEX 



397 



Formaldehyde gas, 382 
Formalin, 385 
Fumigation, 379 

G 

Garbage disposal, 267 
Gaseous disinfection, 382 
German measles, 353 
Germicides, 378 
Gingivae, 29 

care of, 149 
Gingivitis, 151 
Glanders, 354 
Good air denned, 323 
Gonorrhea, 355 
Ground water, 228 
Gums and gingivae, care of, 149 



Habit, 70 

Hands, disinfection of, 386 
Head, carrying forward, 60 
Health education in industry, 318 

officer, 207 

societies, 207 
Heredity, 80 

and conduct, 93 

and environment, 91 

mental, 90 
Hippocrates, 109 
Hookworm, 344 
Hours of work, 304 
Humidifying air, 333 
Hydrocyanic acid, 384 
Hygiene, dental, 17 

industrial, 301 

ocular, 63 

of action, 54 

of central nervous system, 68 

of the emotions, 45 

of mouth, 18 

of nutrition, 33 

of reproduction, 80 

of sex, 104 

personal, divisions of, 17 

preventive, 123 

Bchool, 274 
Hygienist, the dental, 153 
Bygrodeik, 329 



Immunity, acquired, 129 

active and passive, 130 

defined, 125 

essential facts of, 125 

in anthrax and rabies, 115 

local, 129 

natural, 128 

nonspecific, 127 
specific, 128 

theories of, 138 
Iinhoff tank, 264 
Incineration of garbage, 268 
Indigestion, emotional, 45 
Industrial accident insurance, 306 

dentistry, 315 

diseases, 319 

health administration, 307 

hygiene, 301 

medical activities, 312 

sanitation, 311 
Influenza, 184 

cause of, 185 

control of, 186 

immunity to, 186 

morbidity and mortalitv rates, 
185 
Infant care, 100 

standards of, 103 
Inherited diseases and abnormali- 
ties, 88 
Injunction, 197 
Inorganic salts in diet, 37 
Intermittent sand filtration, l'47 
Investing tissues of teeth, 28 
Isolation, 342 
Insurance, accident, 306 



K 



Koch, 112 



Lawrence experiment station, 249 
Laws, public health, 195 

pure food, 210 
Lead poisoning, 319 
Leprosy, 356 
License, nature of, 196 
Lighting, 337 
Lime, 385 
Lister, 112 

Local health administration, 205 
Lysine, 137 



398 



INDEX 



M 

Mastication, 47 

and salivary secretion, 31 
Maternity care, standards of, 98 
Malaria, 357 
Manure disposal, 269 
Measles, 358 

German, 353 
Meat, sanitation of, 222 
Mechanical filter, 240 

ventilation, 332 
Medical activities in industry, 312 
Mendelian inheritance, 80 
Meningitis, cerebrospinal, 347 
Mental concentration, 69 
Mentality and heredity, 90 
Mercuric chloride, 385 
Mercury poisoning, 321 
Miles' process, 246 
Milk, cow's, composition of, 213 

graded, 218 

human, composition of, 39 

in diet, 39 

New York regulations, 220 

remade, 219 

sanitation of, 213 
Milk of lime, 386 
Misbranding, 212 
Mouth, care of the child's, 161 

hygiene, 18 

washes, 160 
Moisture in air, 326 
Mucus, 31 
Municipal health administration, 

205 
Mumps, 359 

N 

Natural disinfection, 380 

ventilation, 331 
Nervous system, hygiene of, 68 
Neurasthenia, 73 
Neurasthenic, the, 78 
Nightsoil, final disposal of, 262 
Nitrogen cycle, 233 
Nitrogenous foods, 35 
Nuisance, 197 
Nutrition, hygiene of, 33 

O 

Obesity, 52 
Occlusion of teeth, 19 
Ocular hygiene, 63 



Odors in air, 326 

Office, disinfection of, 387 

lighting, 338 
Opsonins, 132 

Oral defects and immunity, 128 
Oral prophylaxis, 144 
Orthodontia, 20 
Overwork, 74 
Oxidation, 49 
Oxygen, nascent, 384 



Pacifying devices, 25 
Paratyphoid bacilli in meat, 222 

fever, 360 
Pasteur, 109, 111 
Pasteurization, 218 
Patent medicines, 77 
Pellagra, 38 

Peridental membrane, 28 
Permits, 196 

Personal hygiene, divisions of, 17 
Phagocytosis, 132 
Physical examination in industry, 
312 

of school children, 277 
Phosphorus poisoning, 320 
Pit privy, 259 
Plague, 361 
Pneumonia, 364 
Poisoning, acid, 321 

benzene, 321 

food, 51 

lead, 319 

mercury, 321 

phosphorus, 320 

ptomaine, 223 
Police power, 196 
Poliomyelitis, 362 
Polymeter, 330 
Posture, 59 

Potassium permanganate, 385 ' 
Power of discretion, 196 
Precipitins, 136 

Prepared food, sanitation of, 223 
Prenatal care, 95 
Preschool child, standards, 103 
Preventive hygiene, 123 

medicine, history of, 113 

sanitation, history of, 117 



INDEX 



399 



Privy, deodorizing the, 263 

the pit, 259 

the receptacle, 260 
Prophylactic treatment of teeth, 

153 
Prophylaxis, oral, 144 
Proteins in diet, 35 
Psychrometer, the sling, 329 
Ptomaine poisoning, 223 
Ptyalin, 31 
Public health administration, 188 

laws, 195 
Pure food laws, 210 



Q 



Quarantine, 342 

R 

Rabies, 363 

Eabies, immunity in, 115 

Reactive phenomena, 132 

Receptacle privy, 260 

Regulations, health, 197 

Relative humidity, 328 

Renovation, 342 

Reproduction, hygiene of, 80 

Resistance and hygiene, 123 

Rest after eating, 48 

Rickets, 39 

Rocky Mountain spotted fever, 364 

Round shoulders, 59 

Rural sanitation, 254 



Saliva, 30 

Sand filtration of sewage, 266 

of water, 240 
Sanitation, industrial, 311 

of food, 213 

of school buildings, 296 

preventive, 117 

rural, 254 
Scarlet fever, 365 
School children, dental care of, 286 

physical examination of, 277 

standard requirements for, 299 

treatment of defects, 280 
School dental clinics, 291 

health control, 276 
School hygiene, 274 

administration of, 281 

how taught, 294 



School hygiene — Cont 'd. 

medical personnel for, 276 

scope of, 275 
School sanitation, 296 
Score card for food establishments, 

224 
Scurvy, 38 

Sedgwick-Rafter process, 235 
Self purification of streams, 236 
Sepsis, 378 

Septic sore throat, 366 
Septic tank, 251, 264 
Sewage disposal, 243 

farming, 247 

purification, limitations of, 253 

purification, table of, 255 
Sex education, 104 
Sex, how determined, 86 

hygiene, 104 
Sex-linked characters, 87 
Side chain theory, 139 
Sleep, 70 

Sling psychrometer, 329 
Sludge disposal, 266 
Smallpox, 367 

and vaccination, 114 
Soakage pit, 266 
Societies, health, 207 
Spinal curvatures, 62 
Sprinkling filters, 250 
Standardizing disinfectants, 380 
Standards, for infant care, 103 

for maternity care, 98 

for preschool child, 103 

for school children, 299 
Starches in diet, 35 
State department of health, divi- 
sions of, 203 

department of health, organiza- 
tion, 198 

health administration, 198 

health functions, 195 
Statutory law, 196 
Sterilization, 378 
Stimulants, 76 
Storage of water, 236 
Straddle trench, 258 
Structure of teeth, 25 
Subsurface irrigation, 265 
Sugars in diet, 35 
Sulphur dioxide, 383 
Sunday observance, 7.'! 
Surface irrigation, 265 

water, 228 



400 



INDEX 



Susceptibles, 342 
Sydenham, 109 
Syphilis, 174, 368 
prevention of, 178 
transmission of, 177 



Tapeworms, 223 

Taenia, 223 

Tank, Imhoff, 252, 264 

Tank, septic, 251, 264 

Tea, 77 

Teeth, contact and occlusion, 19 

daily care of, 155 

development of, 21 

form and arrangement of, 18 

function of, 21 

investing tissues of, 28 

method of brushing, 156 

septic, 161 

structure of, 25 
Temperature, 326 
Testing air, 327 
Tetanus, 369 
Thumb sucking, 25 
Theories of disease, 108 

of immunity, 138 
Thermometer, wet bulb, 328 
Tick fever, 364 
Toxins, 131 

Toothbrush, care of, 159 
Toothpicks, 159 

Tooth powders and pastes, 160 
Tooth-cleansing foods, 161 
Trachoma, 370 
Trichina spiralis, 222 
Trichinosis, 222, 371 
Trickling filters, 265 
Tuberculosis, 167 

other than pulmonary, 373 

prevention and control, 171 

pulmonary, 371 

transmission of, 169 



Two-story tank, 250 
Typhoid fever, 373 

epidemic from oysters, 121 
Typhus fever, 374 

U 

Under-eating, 52 

and immunity, 128 
IT. S. Public Health Service, 191 



Vaccination, history of, 114 
Varied diet, 42 
Vaughan, 133 

Ventilation, artificial or mechan- 
ical, 332 

and heating, 330 

economic value of, 336 

heating and lighting, 323 

natural, 331 
Vitamines, 37 
Vision, defective, 285 

W 

Walking, 58 

Water, analysis of, 230 

filtration of, 240 

in the diet, 34 

in the saliva, 31 

purification of, 236 

supply, 226 

sources of supply, 228 

with meals, 48 
Waste disposal, 243 
Whitewash, 386 
Whooping cough, 375 
Women in industry, 305 
Work, change of, 72 



Yellow fever, 376 



